(Stress caused by) physical, environmental and climatic factors.

The genetic differences among populations of a tree species that influence how well individual trees can survive and thrive under different environmental conditions, especially in response to climatic factors and disease pressures.

The process of establishing a forest in an area where there was no previous tree cover/forest before (or not for a long time).

The spread of harmful organisms through the air. Some pest and disease-causing agents can be carried by air currents and deposited onto susceptible trees where they can establish and cause damage.

Any flowering plant that produces seeds enclosed within a protective structure, such as a fruit or nut - unlike gymnosperms which produce seeds without a protective fruit.

Sourcing trees for planting from areas where the current climate matches the projected future climate for the planting area, with the aim of ensuring planted trees are resilient to future climates.

The process by which reactive nitrogen compounds, emitted into the atmosphere from various sources (including aeroplanes, cars, and certain factories), are deposited onto the Earth's surface. This deposition can occur through both wet (e.g., rain, snow) and dry (e.g., gaseous absorption, particle settling) processes.

Regions defined by climate and natural vegetation.

A living organism, or natural substance derived from them, that is used to control pests and diseases.

A set of precautions that aim to prevent the introduction and spread of harmful organisms, including non-native pests, such as insects, and disease-causing organisms (known as pathogens), such as some viruses, bacteria, and fungi.

A range of risks associated with the introduction and spread of harmful organisms, including pests, pathogens, and invasive species, which can negatively impact human, animal, plant, and environmental health. These threats can arise from natural sources, accidental releases, or deliberate acts of bioterrorism.

(Stress caused by) living organisms such as bacteria, viruses, fungi and insects.

A category of trees that have wide, flat leaves rather than needle-like leaves. These trees are usually deciduous and lose their leaves in winter.

A planting area where trees from different places are grown together under the same environmental conditions, so their differences can be compared fairly.

A woodland management approach that involves selectively thinning trees to create a diverse forest structure, whilst maintaining canopy cover.

The uppermost part of a tree, comprising all the branches, leaves, flowers, and fruits that extend from the trunk.

Different tree species that look very similar but are genetically distinct.

A specific variety of tree that has been selected and cultivated for particular desirable traits.

The removal of a plant/tree’s leaves, either naturally due environmental factors like disease or grazing, or through human intervention.

A legally defined geographical area that has been identified following the detection of a quarantine or regulated tree pest or pathogen. It is set up to prevent spread and support monitoring, control, and eradication measures.

The loss or weakening of cultural, historical, and emotional connections that people have with specific tree species.

The benefits that human beings obtain from ecosystems, contributing to our well-being and a healthy planet. Examples include clean air, food, water, recreation, and raw materials (like wood).

Growth from a previously dormant bud on the trunk or a limb of a tree.

The rapid spread of a disease or condition, exceeding what is normally expected.

The process by which water is transferred from the land to the atmosphere, by water leaving the soil (evaporation) and water lost through plant leaves and stems (transpiration).

The degree of genetic and evolutionary similarity between native and non-native tree and plant species.

Members of the farming community that act as a type of knowledge intermediary.

The leafy parts of a tree or plant.

A section of a forest where the trees and other plants are similar in species, age, and structure, and where the soil and land shape (topography) are also alike. See also Mixed-species stand.

A measure of how full a forest area is with trees, usually compared to an optimal or desired number of trees for healthy growth and management.

The fine pellets or powdery material excreted by insects, especially wood‑boring or leaf‑feeding insects, often found on or beneath trees.

A collection of dried fungal specimens, serving as a scientific and historical archive of fungi from around the world. For more information, see The Fungarium | Kew.

A group of seed-producing plants that includes conifers like Sitka spruce. Gymnosperms are characterised by:

• Producing seeds without a protective fruit (unlike angiosperms, which have seeds enclosed in fruits).
• Typically having needle-like or scale-like leaves.
• Often being evergreen and forming large forests, especially in temperate and boreal regions.

Characteristics of the tree that can be passed to their offspring.

The systematic process of identifying and asessing potential threats from non-native tree pests and diseases before they become significant problems.

The set of tree species that a particular pest or pathogen can successfully infest, infect, and use to survive and reproduce.

A tree species that provides resources, such as nutrients, water, or physical support, to another organism, typically a pest or pathogen.

The intentional introduction of a pathogen or pest into a host tree under controlled conditions to study its effects.

A set of internationally agreed standards, guidelines, and recommendations that help countries protect plant health while facilitating safe international trade. They are developed under the International Plant Protection Convention (IPPC), a multilateral treaty overseen by the Food and Agriculture Organisation of the United Nations (FAO). For more information, see IPPC Adopted Standards

A network of physical devices that collect and exchange data with each other and with other systems via the internet. These connected "things" are equipped with sensors, software, and other technologies that allow them to sense their environment, process information, and communicate without human intervention, enabling automation, real-time monitoring, and improved efficiency in various aspects of life and business.

A non-native organism that establishes, spreads, and causes harm to its new environment, threatening biodiversity, ecosystems, and the economy. These species, which can be plants, animals, bacteria, or other life forms, often out compete native species for resources and lack natural predators in their new habitat, leading to significant ecological and economic damage.

People or organisations that help to connect experts or evidence with people who benefit from the information.

Approaches to presenting, packaging and delivering information that are intended to improve engagement with it, and application of it, amongst target audiences.

The process in which new leaves grow and unfold on a tree, usually at the start of the growing season.

Control methods which are designed to kill pests such as grey squirrels.

When populations evolve genetic differences that make them better suited to the specific environmental conditions of their local area, compared to individuals of that species from other areas.

The microorganisms, including bacteria, fungi, and viruses, which live in a particular environment.

A forest stand that contains two or more different tree species growing together in the same area under similar environmental conditions.

Forests made up trees of the same age and from a single species.

Symbiotic relationships between fungi and plant roots.

Soil-based fungi which interact with tree roots and support trees in accessing soil nutrients.

Biodegradable materials made from the root-like structure of fungi (called mycelium) combined with agricultural waste such as straw, husks, or sawdust.

The process by which trees spread into a new area where they were not previously growing, usually from seeds carried in from elsewhere, for example, by wind or animals.

The process by which trees grow back on their own from seeds, sprouts, or seedlings without human planting.

The process by which trees with heritable traits that help them survive and reproduce are more likely to pass those traits on to the next generation.

Where new trees grow naturally from parts of a parent tree (such as roots or shoots) without fertilisation, producing identical copies (clones).

The physical characteristics and structural traits of tree needles, such as their length, width, shape, and surface features, which may influence the tree's resilience to environmental stressors and diseases.

Control methods which are designed to manage or deter pests such as grey squirrels, without causing death.

A (mother) tree that has been naturally pollinated by wind, insects, or other natural methods, rather than controlled or deliberate pollination by humans.

The process by which a tree fertilises a different individual tree, or is itself fertilised by a different individual tree, as opposed to pollen it produced itself.

Observable characteristics, such as height, biomass, leaf shape and so on.

The routes by which organisms turn sunlight, water, and carbon dioxide into food and oxygen.

A living plant tissue responsible for transporting sugars, amino acids, and other organic nutrients created during photosynthesis to all other parts of the plant.

An internal body process that helps an organism survive and reproduce in its environment.

A traceability and assurance document required for the movement of regulated plants, such as trees, saplings, and nursery stock, within a country or trading area (for example, within Great Britain or the EU). It shows that plants have been inspected, produced by a registered professional operator, and comply with plant health legislation. For more information, see Guidance: Plants and wood that need a plant passport for movement within Great Britain.

Individual trees in a forest that have been selected because they show superior traits, such as faster growth, better shape, good health, or higher-quality wood, compared to other trees of the same species. These trees are often used in forestry breeding and seed programmes to improve the overall quality of future forests.

A fine powder produced by plants that contains the male reproductive cells needed for fertilisation.

A descendent or offspring.

​Biological material such as a seed, spore, bud, or cutting, that becomes detached from a parent organism and functions in dispersal and the creation of a new individual.

A forestry term used to describe the location of the stand from which reproductive material (seeds or cuttings) was collected, i.e. their geographical origin.

The inactive, non-feeding stage between the larval and adult stages in the life cycle of many tree‐damaging insects (such as beetles, moths, and flies).

Materials designed to restore, renew, or improve natural systems rather than deplete them.

A structured, step-by-step approach, developed primarily by Forest Research, designed to help managers identify and act on risks to enhance system robustness. For more information, see Forest Research - Resilience Implementation Framework.

The physical structure, shape, and external characteristics of plant roots, including diameter, branching patterns, length, and surface features like root hairs.

A young shoot or cutting from a tree that is grafted onto another plant to grow as part of it.

Geographically defined areas where tree populations have adapted to specific local environmental conditions, such as climate, soil, and elevation, and where seeds or saplings can be sourced for planting with a high likelihood of successful growth.

A specific batch or quantity of seeds, often from a particular source or seed zone.

The process by which a plant, including trees, produces seeds after successful pollination and fertilisation.

The process by which a tree that can produce both male and female flowers fertilises itself using its own pollen.

The process by which some deep-rooted plants take in water from lower soil layers and exude that water into upper, drier soil layers.

The process by which new tree species form over time as populations become genetically different and no longer interbreed.

The specific combinations of tree species found in a particular area, influenced by both environmental factors and interactions between species.

The way that the trunk of a tree grows - this includes characteristics such as the straightness, taper, branching pattern, and overall shape of the tree stem.

Tiny openings on the surface of plant leaves that allow gases like oxygen and carbon dioxide to move in and out, as well as water vapour.

The variation in the physical structure of forest stands, specifically, the diversity in tree sizes, shapes, ages, and spatial arrangements within a forest. This includes differences in canopy layers, the presence of understorey vegetation, and the mix of tree species types (e.g., broadleaf vs. conifer, evergreen vs. deciduous).

A comprehensive, visual, and narrative framework that explains how and why a desired long-term change is expected to happen, mapping the pathway from activities to impact. It acts as a blueprint for planning, evaluation, and decision-making, identifying assumptions, necessary interventions, and intermediate outcomes.

A landscape or scene dominated by trees, forests, or woody vegetation.

Kew launched the UK National Tree Seed Project (UKNTSP) in 2013. The project collected and stored seed from native trees and shrubs throughout the UK. Multiple collections were being made, right across the native range of each species, in order to develop genetically representative collections in the Millennium Seed Bank (MSB). Over 10 million seeds have been successfully stored. For most of these collections each mother tree was georeferenced, and their seed stored separately. For more information, see UK National Tree Seed Project (Legacy) | Kew.

An organism that transmits a pathogen, disease, or parasite from one animal or plant to another.

The degree or severity of a disease.

Carbon-based chemicals produced by living organisms, that evaporate into the air at room temperature.

The uprooting or significant overturning of trees caused by strong winds.

One of multiple possible genetic variants at a particular position on a chromosome. These can influence variation in a tree's traits.

The process of producing new trees from a single parent plant so that all offspring are genetically identical copies (clones).

The study of similarities and differences in DNA between species to understand evolutionary relationships and the genetic basis of differences between species.

Deoxyribonucleic acid - the biological instruction manual found inside every living cell. It dictates how an organism grows, develops, and functions.

The inheritance of traits from parent tree to its offspring via mechanisms other than DNA.

Differences in gene function that arise from modifications to DNA, not changes in the DNA sequence itself.

The heritable materials within and amongst trees (and other woody species) that have economic, environmental, scientific, or societal value.

A reproductive cell that carries half the genetic information needed to form a new individual - in trees this would be an ovule (female) or pollen (male).

The production of a protein from the DNA blueprint.

Methods used to study when and how strongly genes are turned on or off in a tree to understand how they influence traits or responses to the environment.

The movement of genes between tree populations through pollen or seed dispersal, spreading genetic variation.

Planned approaches for managing how genetic material (i.e. genes) moves between tree populations, especially through seed and pollen dispersal, to enhance the adaptability and resilience of forests under climate change.

Refers to genes - the segments of DNA that contain instructions for how living things grow and function.

Means that a trait, condition, or disease is influenced by an individual's DNA.

A situation where a tree population is greatly reduced in size, perhaps due to a recent challenge such as a severe drought or disease outbreak, causing a loss of genetic diversity because only a few individuals survive.

The extent to which specific traits are determined by the tree's genetic makeup and can be inherited by its offspring.

Variation in genetic traits within a species or population.

The random change in gene frequencies in a tree population over time - fluctuations tend to be larger in smaller populations.

Loss of genetic differences among populations, often reducing landscape-level complexity, which may result in reduced adaptability and resilience.

A series of trees connected by an unbroken line of descent from ancestors to descendants (e.g. grandparents, parents, offspring).

Specific DNA sequences that vary between individuals and can be used to identify trees, assess genetic diversity, and track traits like growth or disease resistance.

An estimate of the relative performance of a tree for in a particular trait, based on its genetics.

Differences in DNA between individuals, such as changes in genes.

The natural differences in DNA sequences among individuals of the same species.

The study of how traits are passed from parents to offspring

The complete set of genetic material in an organism. It includes all of the organism’s DNA, which contains the instructions needed for growth, development, functioning, and reproduction.

The process and result of reconstructing the complete DNA sequence of a tree from fragmented sequencing data. These assemblies are essential for understanding the genetic makeup of different tree species and identifying traits like resistance to disease.

Comprehensive representations of the DNA sequence from a single tree. These sequences serve as a template or baseline for comparing the genomes of other individuals within the species.

The complete DNA blueprint of individual trees, which is used to understand how genetic variation influences tree growth, resilience, and adaptation to environmental conditions, especially under climate change.

The process of determining the complete DNA sequence of a tree’s genome. This includes identifying the order of all the nucleotides (A, T, C, and G) that make up its genetic material.

Genetic differences that are identified across the entire genome of an individual organism.

The statistical relationship between genetic variations (genotypes) and environmental factors. It is a method used to study how organisms adapt to their local environments by identifying specific genes that are associated with particular environmental conditions.

A research method used to identify specific regions of a genome, called loci, which are statistically associated with traits such as resistance to disease.

Analysis of the genetic information obtained from the DNA of tree populations.

The underlying genetic features, such as DNA sequences, genes, and structural variants, which contribute to resistance or susceptibility to disease.

The specific influence of DNA-level variation, such as genes, loci, and single nucleotide polymorphisms (SNPs), on adaptive traits in trees. It goes beyond general heritability to identify which parts of the genome are responsible for traits like disease resistance, stress tolerance, water use efficiency, and growth and stem form.

The variation found across the entire genome of individual trees within a species or population.

A predictive measure of how well a tree's genetic makeup (its genotype) matches the environmental conditions it is likely to face in the future, especially under climate change.

A method that uses DNA information from many markers across the genome to predict the relative performance of an individual for a particular trait.

Where entire regions of DNA are inverted, duplicated, deleted or moved elsewhere in the genome in some individuals.

The differences in DNA sequences among individual trees, which can influence their susceptibility or resistance to disease.

The study of an organism’s complete set of DNA, including all of its genes.

The specific combination of genetic variants a tree has, which may influence how it grows and interacts with its environment.

The breaking up of forests into smaller, isolated areas, which limits the movement of seeds and pollen and reduces migration (and gene flow) between tree populations.

A measure of how much of the differences in a trait between individuals in a population are due to genetic differences.

Being very similar or uniform - e.g. a genetically homogeneous group of trees will have little genetic variation within them.

The process by which two genetically distinct species, strains, or populations interbreed, producing hybrid offspring with a combination of traits from both parents. It can occur when related pests or pathogens come into contact and reproduce. The resulting hybrids may be more vigorous, adaptable, or damaging than their parent organisms.

A reduction in growth, health, or survival in trees caused by breeding between closely related individuals.

The study of how environmental conditions (like climate, soil, and terrain) influence the genetic variation of tree populations across different locations.

Specific, identifiable positions or regions in a tree's DNA where genetic variants can occur.

DNA that is sequenced in sections that average thousands of base pairs in length, rather than the more commonly used short-read.

In the context of tree genome research, mapping means aligning short DNA sequences (called reads) from individual trees to a known, high-quality reference genome. Essentially a complete and well-assembled version of the tree’s DNA.

Short, repetitive sequences of DNA used by scientists to study genetic variation and relationships between trees.

A spontaneous change of the DNA sequence of a tree at a particular location in the genome. This can sometimes lead to changes in traits.

The fundamental building blocks of DNA: adenine (A), cytosine (C), guanine (G), and thymine (T). Changes at single bases can identify individual differences.

A structure in plants that contains the female reproductive cell and can develop into a seed after fertilisation.

The complete set of genetic materials found across all individuals of a species.

The ability of a tree to change its growth or characteristics in response to different environmental conditions.

The evolutionary relationships between different tree species.

The evolutionary history, relationships, and lines of descent among groups of organisms (species, genes, etc.), usually represented by a branching tree diagram. They illustrate how species share common ancestors and, through branches, show which groups are more closely related based on genetic or physical traits.

The science of using whole-genome data to understand how species are related and how they evolved.

Small, double-membrane structures found in the cells of plants and algae that act as "factories" for making and storing food and pigments.

Resistance to a pest or disease controlled by many genes, each contributing a small effect, which can result in broader and more durable protection.

A section of DNA that is the blueprint for a protein. Proteins are large molecules that carry out lots of different functions in an organism, especially in the cells.

A method used to identify regions of the genome associated with variation in particular traits.

In the context of tree genome research, a read is a short fragment of DNA sequence that has been decoded by a sequencing machine.

Carefully constructed representations of the complete DNA sequence of a single tree. These assemblies serve as a genetic blueprint for the species and are used as a standard for comparing the genomes of other individuals.

The molecules that carry genetic instructions from DNA and help regulate how cells function, especially how they respond to stress or infection.

In the context of tree genome research, a scaffold is a stretch of DNA sequence that may contain gaps, but the order and orientation of the pieces are known.

A DNA sequencing method where the DNA is broken into small fragments, and each fragment is sequenced individually.

When a tree’s resistance to a particular pest or disease is controlled by one specific gene, which can give strong but narrowly focused protection.

A variation at a single position in a DNA sequence among individuals.

A serious disease of oak trees (trees in the Quercus genus) which was first observed in the UK late in the 20th century. It can kill oak trees within four to six years of the onset of symptoms.The disease is found mostly on mature oak trees, but younger trees can also be affected. It is caused by multiple agents, especially bacteria, and thousands of trees are affected. For infection to occur, it is likely the trees need to be weakened (predisposed) by certain factors, especially environmental factors. For more information, see Acute oak decline - Forest Research.

A non-regulated invasive bark boring beetle believed to be a secondary colonist of diseased ash trees. It is related to the emerald ash borer (Agrilus planipennis) but is thought to be much less destructive to living trees. It was first discovered in the UK in 2023 in Surrey.

A highly destructive disease of ash trees (Fraxinus species), caused by the fungus Hymenoscyphus fraxineus, which leads to leaf loss, crown dieback, and often the death of affected trees. It is present in the UK and particularly affects the native common ash. For more information, see Ash dieback (Hymenoscyphus fraxineus) - Forest Research.

A destructive behaviour carried out by grey squirrels (Sciurus carolinensis) where they remove tree bark in order to access the sweet, sap-filled phloem tissue beneath. Bark removal can severely impact tree health, lead to tree death and significantly reduce the economic value of timber.

A localised area of dead or damaged bark and underlying tissue on a tree’s stem, branch, or trunk, usually caused by pathogens or injury.

A genus of longhorn beetles within the family Cerambycidae, known for their role as vectors of the pine wood nematode (Bursaphelenchus xylophilus), the causal agent of pine wilt disease (PWD). It is not known to be present in the UK.

A virus that infects the fungus Cryphonectria parasitica, which causes sweet chestnut blight. CHV1 is known for inducing hypovirulence, meaning it reduces the fungus’s ability to cause severe disease.

A fungal disease of conifer trees, especially pines (Pinus species), that causes red bands on needles, premature needle loss, reduced growth, and in severe cases can lead to tree death. It is caused by the fungus Dothistroma septosporum which is present in the UK. For more information, see Dothistroma needle blight (Dothistroma septosporum) - Forest Research.

A highly destructive disease of elm trees caused mainly by the fungus Ophiostoma novo‑ulmi. It is spread by elm bark beetles and blocks the tree’s water‑conducting tissues, leading to wilting and death. It is present in the UK and has killed tens of millions of elm trees since it was accidentally introduced, likely in the 1960's. For more information, see Dutch elm disease (Ophiostoma novo-ulmi) - Forest Research.

A small but highly destructive insect that attacks spruce trees by burrowing under the bark, where it damages the tissues that transport water and nutrients, often weakening or killing the tree, especially when beetle numbers are high. It is present in the UK. For more information, see Larger eight-toothed European spruce bark beetle (Ips typographus) - Forest Research.

A highly destructive non‑native beetle that attacks ash trees by tunnelling under the bark, damaging the tissues that carry water and nutrients and usually causing the tree to die. It is not known to be present in the UK. For more information, see Emerald ash borer beetle (Agrilus planipennis) - Forest Research.

A non-native, invasive species originally from eastern North America. They were introduced to Great Britain in the 19th century and have since spread widely, now numbering over 2.7 million individuals across the UK. For more information on the management of grey squirrels, see Management of grey squirrels - Forest Research.

Stem cracking.

Tunnels chewed through the wood by insect larvae.

Abnormal plant growths, often called swellings or deformities, which develop as a result of insect larvae feeding on plant tissue.

A localised area of damaged or abnormal tissue, often appearing as a sunken, discoloured, or dark area on the bark, branches, or leaves. These lesions can be caused by various factors like fungal infections, bacterial diseases, or even physical wounds.

A disease caused by the fungus Erysiphe alphitoides and it is a common pathogen of oak throughout Europe. Erysiphe attacks young leaves and soft shoots, covering them with a felty-white mycelium, causing them to shrivel and blacken. For more information, see Oak mildew - Forest Research.

A condition affecting oak trees that causes stem cracking, which significantly reduces the value and long-term usability of harvested timber. Whilst several biological factors and environmental triggers are known to contribute to shake, the exact causes remain unclear. For more information, see Report instances of oak shake - Forest Research.

An organism or agent that can cause disease. Pathogens include viruses, bacteria, fungi, and protists. They can infect a wide range of hosts, including plants and animals. Pathogenicity is the ability of a pathogen cause disease.

Any organism including insects, fungi, bacteria, viruses, nematodes, or other pathogens that can cause harm to trees or tree products (in the context of forest protection).

A fungus‑like plant pathogen that infects trees, particularly conifers such as western hemlock and Douglas fir, causing needle loss, shoot dieback, and stem damage that can weaken or kill affected trees. It is present in parts of the UK. For more information, see Phytophthora pluvialis - Forest Research.

Plant‑damaging microorganisms that live in soil and water and can infect tree roots, weakening trees and contributing to decline, particularly by damaging fine roots and making trees more vulnerable to stress and dieback. For more information, see Phytophthoras - Forest Research.

A native woodland moth whose caterpillars feed on the needles of pine trees, sometimes causing heavy defoliation and weakening trees during population outbreaks. For more information, see Pine Beauty | Butterfly Conservation.

A serious disease of pine trees caused by the pine wood nematode (Bursaphelenchus xylophilus), a microscopic worm that blocks the tree’s water‑conducting tissues, causing rapid wilting, needle browning and usually death of the tree. It is not known to be present in the UK. For more information, see Pine wood nematode (Bursaphelenchus xylophilus) - Forest Research.

A microscopic, worm‑like organism that infects pine and other conifer trees, causing a deadly disease known as pine wilt, which disrupts water movement in the tree and often leads to rapid tree death. It is not known to be present in the UK. For more information, see Pine wood nematode (Bursaphelenchus xylophilus) - Forest Research.

'International Standards for Phytosanitary Measures' definition: A pest which could cause economic harm in an areas, but is either not present there, or is present but not widespread and is being officially controlled. Plant materials containing the pest cannot be moved. For more information, see Glossary of phytosanitary terms - International Standards for Phytosanitary Measures.

'International Standards for Phytosanitary Measures' definition: A pest which is already present in an area. A level of pest infestation may be tolerated, however plant infestations over a certain threshold would result in an unacceptable economic impact. For more information, see Glossary of phytosanitary terms - International Standards for Phytosanitary Measures.

'International Standards for Phytosanitary Measures' definition: A quarantine pest or a regulated non-quarantine pest. Regulated pests are detected and intercepted at borders and inland on various commodities and products. The relevant tree and/or plant health authorities should be notified immediately following a suspected sighting of a regulated pest. For more information, see Glossary of phytosanitary terms - International Standards for Phytosanitary Measures.

A bacterial infection that causes white foam to seep from crevices in the bark.

The process by which certain bacteria, fungi, and plants form spores to survive harsh conditons or reproduce.

A destructive fungal disease of sweet chestnut trees (Castanea species) caused by Cryphonectria parasitica. The fungus infects the bark, forming cankers that girdle branches or stems, cutting off nutrient flow and often leading to dieback or death of the tree. It is present in parts of the UK and is subject to official control measures. For more information, see Sweet chestnut blight (Cryphonectria parasitica) - Forest Research.

The various routes through which pests and pathogens can spread, including human assisted pathways such as through the movement of live plants and plant products, timber and wood products, dirty tools and machinery, and in soil and growing media.

A serious plant disease which infects the water‑conducting tissues of plants and blocks the movement of water and nutrients. It can affect a very wide range of trees and plants, including oak, and elm often leading to severe decline or death of infected plants. It is not known to be present in the UK. For more information, see Xylella (Xylella fastidiosa) - Forest Research.

An insect whose larvae cause galls (abnormal growths) on yew trees. These galls typically develop from buds and are frequently observed in areas where ancient yew trees are experiencing decline.

Broadleaf deciduous trees of the genus Fraxinus, including native species such as common ash/European ash (Fraxinus excelsior) , which are valued in Britain for their strong, flexible timber and high ecological importance, but are now severely threatened by ash dieback disease. For more information, see Ash (AH) - Forest Research.

Fast‑growing broadleaf deciduous trees of the genus Betula, including native species such as silver birch (Betula pendula) and downy birch (Betula pubescens), which are widespread across Britain and valued as pioneer species for their ability to colonise open ground and support woodland biodiversity. For more information, see Birch - Forest Research.

A rare, native Scots pine (Pinus sylvestris) woodland found mainly in the Scottish Highlands. It is an ancient, light‑demanding habitat that grows on poor, acidic soils and is valued for its rich biodiversity, natural heritage, and importance for conservation.

Cone-bearing and usually evergreen trees. They are a distinct group of trees that are economically significant due to their ability to grow quickly even on poor soils and in harsh climates. These trees yield timber that is highly suitable for industrial use, which has led to their widespread planting and management across many countries. Examples of conifer trees found in the UK include Scots pine, Douglas fir, and Norway spruce.

Tall evergreen conifers of the genus Pseudotsuga, native to western North America and widely planted in Britain for commercial forestry, where they are valued for fast growth, high‑quality timber, and importance as a principal forestry species. For more information, see Douglas fir (DF) - Forest Research.

Fast‑growing deciduous broadleaf trees of the genus Betula, specifically Betula pubescens, native to Britain and valued as pioneer species that readily colonise open and wet ground, particularly on moist or peaty soils, helping to establish woodland and support biodiversity. For more information, see Downy birch (DBI) - Forest Research.

Broadleaf deciduous trees of the genus Ulmus, traditionally found in British landscapes, recognised by their oval, toothed leaves and spreading crowns, and historically valued for timber and amenity planting in towns and countryside. It has suffered major decline in the UK due to disease, particularly Dutch elm disease (DED) caused by the fungus Ophiostoma novo-ulmi.

One of the two native elm species in Britain (the other being wych elm, Ulmus glabra). It was once widespread across the UK landscape but has been heavily affected by Dutch elm disease (DED).

Broadleaf deciduous trees of the genus Quercus, commonly found in British woodlands and forests, recognised for their strong timber, characteristic lobed leaves, and acorns, and including native species such as pedunculate oak (Quercus robur). For more information, see Oak - Forest Research.

Tall evergreen conifers of the genus Picea, native to northern and central Europe and widely planted in Britain for forestry, where they are valued for fast growth, straight stems, and their timber used in construction, paper, and other wood products. For more information, see Norway spruce (NS) - Forest Research.

Evergreen conifer trees belonging to the genus Pinus, identified by their needle‑shaped leaves and woody cones, and are widely grown in British forests for timber and ecological value. For more information, see Pine - Forest Research.

A genus of flowering plants in the Rosaceae family that includes economically and ecologically important species such as almond (Prunus dulcis), and wild cherry (Prunus avium). These species are native or naturalised in the UK and are being studied for their susceptibility to Xylella fastidiosa.

Fast‑growing evergreen conifer trees of the genus Pinus, native to Scotland and widely planted across Britain, recognised for their tolerance of dry, poor soils, light‑demanding pioneer nature, and important role in timber production and ecologically significant pinewood habitats. For more information, see Scots pine (SP) - Forest Research.

Fast‑growing deciduous broadleaf trees of the genus Betula, specifically Betula pendula, native to Britain and recognised by their white peeling bark, light crowns, and important role as pioneer species that quickly colonise open ground and support woodland biodiversity. For more information, see Silver birch (SBI) - Forest Research.

Fast‑growing evergreen conifer trees of the species Picea sitchensis, native to the west coast of North America and widely planted in Britain, recognised for their ability to grow productively in cool, wet conditions, their importance as a major commercial timber species, and their dominance in UK forestry plantations. For more information, see Sitka spruce (SS) - Forest Research.

Large, fast‑growing deciduous broadleaf trees of the genus Acer, specifically Acer pseudoplatanus, introduced to Britain several centuries ago and now widespread, valued for their tolerance of wind, pollution and a wide range of soils, and commonly found in woodlands, parks and the wider landscape. For more information, see Sycamore (SY) - Forest Research.

One of the two native elm species in Britain (the other being field elm, Ulmus minor). It is indigenous to the UK and has historically been a common part of the British landscape, especially in upland and northern areas. Like other European elms, wych elm is highly vulnerable to the fungal pathogen Ophiostoma novo-ulmi, which causes Dutch elm disease (DED) that has devastated elm populations since the 1970s.

One of the oldest living trees in northern Europe, yew is one of the three conifers native to Britain alongside Scots pine and juniper. Unlike other conifers, yew trees grow succulent (but poisonous) red fruits instead of cones. For more information, see Yew | Tree species | Forestry England.

Measures how fast sound waves travel through the wood, providing insights into wood stiffness and potential defects.

Arboriculture is the scientific study and practical cultivation of individual trees, shrubs, vines, and other perennial woody plants for their care, management, and benefit to society. An Arboriculturist (or Arborist) is a professional in the practice of Arboriculture.

A non-destructive tool that uses sonic waves to create an image of a tree’s internal structure, which can reveal decay, and other defects.

An interdisciplinary field that uses computer science, statistics, and biology to analyse and interpret biological data.

The use of data-driven analytical frameworks and predictive tools to assess and anticipate risks posed by pests, diseases, and environmental stressors to tree species.

The process of removing the cuticle, or outer layer, of a plant or insect, or the extraction of cuticular waxes from these cuticles.

The scientific method of dating based on the analysis of patterns of tree rings. These rings, formed annually, reflect variations in climate and environmental conditions during the tree's lifespan, providing a record of past events and allowing for the precise dating of wood samples. It can also be known as tree ring analysis.

An experiment in which individual needles are detached from a tree, maintained under controlled conditions and evaluated for their response to biotic/abiotic treatment.

The construction and analysis of mathematical models of ecological processes, including both purely biological and combined biophysical models. Models can be analytic or simulation-based and are used to understand complex ecological processes and predict how real ecosystems might change.

The process of using mathematical and computational models to simulate and study how biological traits, genes, or species change over time through evolution.

A tool used in forestry economics and policy analysis to represent the complex interactions within the forestry sector, combining biophysical and economic elements. These partial-equilibrium models are used to understand and forecast how changes in one part of the sector (e.g., timber supply) might affect other parts (e.g., timber prices or forest management practices). They are crucial for informing policy decisions related to forest management, timber markets, and the broader bioeconomy.

A controlled environment used for growing and studying plants under regulated conditions.

A technique where a part of one tree (such as a shoot or bud) is joined onto another tree so that they grow together as one plant, often to reproduce desirable traits like high yield or good wood quality.

The measurement of how a material reflects light across many different wavelengths, helping to identify its composition or condition.

A scientific method used to detect early signs of stress in trees, whether caused by environmental factors like drought or biological threats such as pathogens.

A remote sensing method that uses laser light to measure distances and create detailed 3D representations of surfaces.

An analytical technique used to identify and measure chemicals in a sample. LC-MS combines two methods: Liquid Chromatography (LC) separates the components of a mixture. Mass Spectrometry (MS) identifies and quantifies those components based on their mass.

The use of DNA-based technologies to enhance traditional tree breeding programmes, accelerating the development of trees with desired traits like disease resistance and climate resilience.

The process of capturing images at a few specific wavelengths across the electromagnetic spectrum (like red, green, blue, and infrared), allowing us to see details that aren’t visible in regular photos. It helps identify materials, detect changes, or analyse objects based on how they reflect light in different bands.

A fundamental process in molecular biology and genetics that enables the isolation and purification of DNA or RNA from various biological samples.

A process to identify appropriate phytosanitary (plant health) measures required to protect plant resources against new or emerging pests and regulated pests of plants or plant products. It evaluates biological or other scientific and economic evidence to determine whether an organism is a pest, whether it should be regulated, and the strength of any phytosanitary measures to be taken against it.

The study of the functions of a plant, encompassing its internal processes, how it interacts with its environment, and its life cycle.

Variables that provide an indirect measure of a target trait, but which are much easier to measure.

A technique used in genomics to discover and map thousands of genetic markers (specifically Single Nucleotide Polymorphisms or SNPs) across the genome.

The scanning of the earth by satellite or high-flying aircraft in order to obtain information about it.

A minimally invasive testing technique that measures wood resistance using a fine drill needle.

A process that evaluates the likelihood and possible impact of future threats on tree health and ecosystems.

The science and practice of cultivating and managing forest stands to ensure their long-term health, productivity, and resilience for various societal needs. It involves activities such as site preparation, regeneration, thinning, pruning, harvesting, and pest management to influence the forest's structure and function, integrating ecological principles and management objectives to produce sustainable forest ecosystems.

A non-destructive testing technique that assesses the internal condition of trees by analysing how sound waves travel through the wood.

The unique patterns of electromagnetic radiation (light) that an object or material reflects or emits across different wavelengths.

A technique used to make trees flower earlier by manipulating environmental conditions specifically, by providing longer daylight hours, elevated carbon dioxide levels, and short artificial winters. This method does not involve genetic modification.

A scientific instrument used to measure water in plant tissues, particularly in tree stems and sometimes leaves. It helps researchers and foresters understand how much water a plant is retaining or losing, which is crucial for studying drought stress, irrigation needs, and overall plant health.

The science of naming, describing and classifying organisms and includes all plants, animals and microorganisms of the world.

A type of evolutionary tree (diagram) that not only shows the relationships between species but also incorporates estimates of divergence times, i.e., when different species or lineages split from a common ancestor.

The study of RNA transcripts produced by tree cells in response to infection by a bacterium.

The study of annual growth rings in trees to understand their historical growth patterns, environmental conditions, and responses to stressors.

A wind sensor that uses ultrasonic sound waves to precisely measure wind speed and direction.