The Dictionary of Forestry by John A. Helms. Recommend every student buy this book. Using it could raise your GPA 0.9 or better.
Reforestation Practices in Southwest Oregon and Northern California, edited by Steve Hobbs.
Regenerating Oregon's Forests, edited by Brian Cleary
The Forest Nursery Manual, edited by Mary Duryea and Tom Landis
A good book to buy if you have a long term interest in definitions is
A Dictionary of Ecology, Evolution, and Systematics, Cambridge University Press
When it comes to definitions, you can not know too many! Also, do not be afraid to look for definitions in a good college dictionary.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
CLICK ONE OF THESE LETTERS TO GET YOU CLOSER TO THE ANSWER TO ONE OF ROBIN'S QUIZ QUESTIONS (KNOCK! KNOCK!!)
Accuracy- In a statistical sense, the success of estimating the true value of a quantity. Sometimes defined the same as precision, but not here. See Precision.
Acclimation- phenotypic adaptation to environmental fluctuations; the gradual and reversible adjustment of physiology or morphology as a result of changing environmental conditions
Acre- a unit area equaling 43,560 square feet.
Advance Regeneration- Young tree that have become established naturally before timber harvest
Allelopathy- The influence of plants upon each other through products of metabolism. For instance, certain plants will not grow under walnut trees because of the chemicals coming off the leaves.
Apical dominance- the inhibition of the development of the lateral buds by hormones.
Argillic- An increase in clay content in subsoil relative to overlying soil horizons caused by translocation of clay minerals during leaching. Argillic horizon.
Aspect- The direction toward which the slope faces.
Autecology- Relationship of individual organism to the environment.
Avoidance - Stress avoidance is stress resistance by avoiding thermodynamic equilibrium with the stress. Avoidance is excluding the stress by physical barriers which insulate the cells or steady state exclusion of the stress by chemical or metabolic barrier (Levitt 1972). See Tolerance.
Bar - a measure of pressure, equal to ~ 1 atmosphere. One megapascal is equal to 10 bars.
Bias- In a sampling sense, a systematic distortion that may arise from many sources, such as a flaw in measurement, method of sample selection, or technique of estimating a parameter.
Boyle, Dr. Jim- any nice guy ecologist as in "he is a Jim Boyle"
Breeding Zone- A geographical area of defined boundaries and altitudinal limits, from which trees will be selected and bred as a genetically improved strain normally intended for planting in the same area.
Brush- Hardwood shrubs and trees that often interfere with reforestation and afforestation.
Bulk Density- The mass or weight of oven-dry soil per unit of bulk volume.
Cavitation-the rapid formation and collapse of vapor pockets in a flowing liquid in regions of very low pressure. The xylem cells in a seedling cavitate as the seedling fails to take up water under drought conditions. See 'plant moisture stress'.
Caliper- this is another term for seedling diameter.
Chilling requirement- time required at low temperatures for a plant or seed to overcome dormancy(rest).
Cohort- A member of a group with like characteristics
Cold Hardiness- The level of a plant's resistance to damage from low temperatures. Also called frost hardiness.
Colloids- Gel-like mineral composites
Damping off fungi-Fusarium spp, a disease that attacks the roots of nursery seedlings leaving the root unable to uptake water and nutrients.
Direct Seeding- The process of reforestation by applying seed to the site either by broadcasting it from the air or ground or by placing it in specific spots on the ground.
Dormancy- A state in which viable seeds, spores, or buds fail to germinate under conditions favorable for germination or vegetative growth. See also quiescence and rest.
Drought - Moisture imbalance when loss of water through foliage exceeds uptake of water, predominately by roots.
Endemic- Native to a particular locality.
Back to top
Field Capacity- Soil water content resulting after the free water has been allowed to drain from a saturated soil for 1-2 days; expressed as a percentage on a dry-weight basis.
Foliar-active- A description for herbicides that enter plants through the foliage
Frequency- The percentage or proportion of plots or areas on which a species or other entity was found relative to the total number examined - synonymous with stocking, occurrence.
Fusarium- A disease species often found in conifer nurseries; causes damping off. It cannot survive in forest soils.
Genetic markers- Physical expression of variants of individual genes which are often used in genetic analysis.
Germination- The beginning of growth of a mature dormant seed.
Genotype- The genetic composition of an individual.
Hartig net- Hyphal network of ectomycorrhizae which penetrates between root cortical cells of the host. (Facilitates the exchange of nutrients between fungus and plant roots)
Height- height is usually measured from the groundline of the seedling stem to the tip of the terminal bud. In hardwoods, like Alder or Eucalyptus, height may be measured to the highest point on the seedling if the seedling droops a lot. Other ways to measure height are from a marked (painted) point 1 inch above ground to the terminal bud.
Hectare - 100 meter by 100 meters or 10,000 square meters. How many acres are in a hectare?
Height/diameter ratio- height divided by diameter (units need to be the same such as 75cm/.46cm [or 4.6mm]. A useful term for understanding the competitive ability of a seedling.
Herbicides- Pesticides used to kill or control the growth of plants.
Hyphae- A thread-like multinucleate tube with a cell wall; the organ of vegetative growth in most fungi. Hyphae increase in length by growth at their tips and give rise to new hyphae by side-branching.
Hypo hatchet- A hatchet that injects a present amount of herbicide into tree stems on impact
Imbibition- the process in which water is taken up by a seed at the beginning of germination.
Inoculum- Portions of a pathogen capable of causing infection or initiating mycorrhizal upon contact with the host.
Intensive survey- Any survey effort that requires sampling and data collection according to a predesigned plan for coverage of the area and observations to be made
Jordanon- A microspecies, race or other infraspecific group.
Jungle- thick, secondary vegetation. Often used by parents as in "My God! Your room looks like a jungle!
Kipuka- An island of vegetation isolated by lava.
Lateral- At, on, or of the side.
Leader- The terminal or topmost shoot
Lenticel- A pore on the surface of the stems of some plants, allowing gas exchange between the stem and the atmosphere. Lifting- The process of digging or pulling tree seedlings from the nursery seedbeds or planting beds prior to bareroot planting in the field or in a transplant bed.
Lignin- A complex aromatic compound which is deposited in the cellulose cell walls of the xylem and sclerenchyma during the process of secondary thickening. Wood is made mostly of lignin.
Litter- Dead plant and animal material on the surface of the ground, above the humus layer.
LT50- temperature at 50% lethality. It is a quantification of frost resistance.
Macroenvironment- The general environment of a broad area
Mass wasting- Land sliding. (No, it's not what happens at a fraternity party or a Grateful Dead show)
Medium- A solid or liquid substrate containing all the materials necessary for growth, used by bilogists for the cultivation of organisms such as bacteria, fungi, and algae, and also for the growth of tissue cultures.
Membrane- A thin sheet of soft material which protects and encloses cells and organelles. Membranes control the movement of substances in and out of cells and organelles.
Mesic- Having moderate amount of moisture; neither hydric nor xeric
Microenvironment- The immediate environment of a specific habitat; often the area surrounding an individual seedling
Milacre- One thousandth (1/1000) of an acre
Morphology- Form and size of organisms or parts of organisms
Mutation- A change in the sequence of nucleotides in the DNA of a cell. Mutations result in variation between individuals and the natural selection of this variation leads to evolution.
Mutualism- The kind of symbiosis in which each partner in the relationship gains something from the other.
Mycelium - The vegetative part of a fungus, composed of hyphae (filamentous elements).
Mycorrhizae - A symbiotic or non-parasitic association between the root or rhizome of a green plant and a fungus. Also, the structure produced by the combination of the modified rootlet with fungal tissue.
Back to top
Natural selection- An evolutionary process in which organisms with certain characteristics produce more offspring than those lacking such characteristics in a given environment
Niche- The position and activities of an organism in its habitat. Each species has its own niche, and competition occurs when the niches overlap.
Nitrate- An inorganic ion present in the soil, which is an important nutrient for plants. Nitrate provides nitrogen for the synthesis of amino acids and other nitrogen-containing compounds, e.g. nucleotides.
Nitrogen cycle- The cycle of the element nitrogen through ecosystems. Organisms need nitrogen in order to synthesize amino acids and protein. Nitrogen is taken up from the soil by plants in the form of nitrate and converted to plant protein.
Nitrogen fixation- The reduction of gaseous nitrogen to ammonia or other inorganic or organic compounds by microorganisms or lightening.
Nonselective herbicide - Formulations of herbicides that destroy or prevent plant life in general, without regard to species.
Nutrient- An inorganic substance which plants require for growth. Nutrients are taken up from the soil by the roots, e.g. nitrate and phosphate.
Osmosis- Diffusion of a solvent through a semipermeable membrane from a region of low solute concentration to one of high solute concentration.
Overstory- The trees that form the upper most canopy layer in a forest.
Parameter- Any quantitative characteristic or attribute of an individual or population.
Parasite- An organism which takes all its nutrients from the tissues of another organism, usually with harmful effects. Many fungi and bacteria are parasites.
Pathogen- An organism which causes disease or illness in another organism. Many viruses, fungi, and bacteria are pathogens.
Phenology- the study of organisms and their activities in relation to the seasons of the year. Also, off-cycle phenology.
Phenotype- The appearance of an individual for one or more traits, which is the product of the interaction of the individual's genes and its environment.
Phosphate- An inorganic ion present in the soil, which is an important nutrient for plants. Phosphate is used in the synthesis of ATP during photosynthesis and respiration. It is also used in the nucleotide molecules of nucleic acids.
Photoperiod- Duration of light, usually expressed in hours, within a 24-hour day
Photosynthesis- The process by which plants use energy from sunlight to produce carbohydrates from carbon dioxide and water. Sunlight energy is captured by molecules of chlorophyll in the chloroplasts of cells in green leaves.
Phloem- One of the conducting tissues in the vascular system. Phloem, unlike xylem, is mainly a living tissue, whose cells contain cytoplasm. The phloem can translocate substances in both directions, and its main function is to translocate the products of photosynthesis from leaves to other parts of the plant.
Polybag- In tropical countries (Africa, Latin America, Southeast Asia) the container system utilizes a black plastic bag called the "polybag", 1 mil or greater thickness, one or two small holes in the bottom for drainage. The bag is filled with local soil or some mix of soil, organic matter, and ash. The seed is hand poked into the media and a seedling grown.
Precision- The clustering of sample values about their own average; precision is not equivalent to accuracy. It is possible to be very precise, yet not at all accurate. See Accuracy.
Pronoun- A word used to replace or substitute a wide variety of nouns. (It is not a professional noun that gets paid, while a noun does not!)
Propagation- The process of reproduction either by natural or artificial means.
Propagules- Any part of the plant that may be used to propagate it, either sexually or vegetatively.
Puddling- Loss of soil structure
Quiescence- A temporary resting phase characterized by reduced activity, inactivity or cessation of development. Do not confuse this term with the state of dormancy called rest. Quiescence is a dormancy state induced most often by drought or a factor external to the plant.
Regeneration- The young trees on an area representing early stages in the renewal of a forest stand
Regeneration Goal- The silviculturally prescribed stocking percentage, density, and kind of tree to be established on an area in a specified period of time
Regeneration period- The time required for the establishment of a stand by natural or artificial regeneration, which may include the time required for pre-harvest planning and harvest of the previous stand
Rhizo- - prefix meaning "root"
Rhizome- An underground stem that produces roots and supports above-ground stems
Root Collar- The point of separation between the stem and root of a plant
Root Regeneration Potential or Capacity- The number and/or total length of roots grown by a tree seedling under controlled test conditions
Root:shoot ratio- Root weight divided by shoot weight. Can also be root volume/shoot volume. See also height/diameter ratio.
Rotation- The number of years between the regeneration of a stand and its final harvest
Sample- The observed or measured part of a population
Sampling Intensity- The number of observations or measurements required to sample a population with a prescribed degree of precision
Scalping- Removal of vegetation and other organic or inorganic material to prepare a planting spot
Scree- Loose rock or gravel on a steep slope
Screwed - This is what happens to students who do not study and party too much. Students are one of a few classes of people that can be both the "screweee" and "screwer" at the same time in the process of screwing themselves. Old English, comes from screawd for someone who thinks beer comes in corked bottles.
Seedbed- The soil or forest floor on which seed falls
Seedbed Density- In nursery practice, the number of seedlings grown pre area of seedbed (usually expressed in #/ft2or #/M2)
Seed crop- The amount or number of seeds produced by a given species in a given year
Seed Zone- Area having defined boundaries and altitudinal limits, within which soil and climate are sufficiently uniform that it is expected that seed can be freely moved without problems of maladaptation
Self-shading- Of a seedling, the ability to shade its base with its branches
Seral- An early stage in plant succession that follows natural or human-caused disturbance
Shade-intolerant- Plant species adapted to reproduce and thrive in the open
Shade-tolerant- Plant species adapted to reproduce and thrive in the shade
Shoot:root Ratio- See top:root ratio
Soil Compaction- An increase in soil bulk density from an undisturbed state
Soil field capacity- The soil water content after gravitational water drainage has become very slow and the water content becomes relatively stable
Stockable plot- A plot on which 50% or more of the area is biologically and physically suitable for seedling establishment
Stocking- A measure of the proportion of the area actually occupied by trees (percentage of an area stocked)
Stocking Standard- Agreed-upon classes of stocking with implications for what level is satisfactory; also, the legally prescribed minimum stocking required to comply with conservation laws
Stomata- Openings or pores in the leaf surface through gas exchange occurs. Each stomate is surrounded by two guard cells that regulate the size of the opening
Stratification- The exposure of seed to a cold, moist treatment to overcome dormancy and promote germination. (The Dictionary of Forestry)
Strobilus- The "cone" of conifers in which seeds or pollen grains are produced
Super cooling- cooling of a liquid below freezing point.
Symbiosis- The living together of two or more organisms of different species.
Back to top
Target seedling concept- The idea of targeting specific morphological and physiological characteristics that can be quantitatively linked with reforestation success.
Tolerance- Stress tolerance is stress resistance by an ability to come to thermodynamic equilibrium with the stress without suffering injury. Tolerance refers to the plants ability to prevent, decrease or repair the strain induced by the stress. See Avoidance.
Top:root Ratio- The ratio of the length or weight (fresh or dry) of a tree seedling's stem and foliage to the length or weight (fresh or dry) of its roots
Transplant shock - An interruption in the normal growth rate of a seedling after being transplanted. Another term is 'bottle brush' because the needles of the new shoots of Douglas-fir emerge and grow very close together i.e. many needles per unit length of stem.
Tourist - A short term logger who quits as soon as the going gets tough for any reason. [from the book Woods Words by W.F. McCulloch]
Traverse line- A straight route of travel across an area for the purposes of locating sample plots at designated intervals.
Treatment efficacy- How well a treatment achieves its goal.
Tubing- The practice of placing a plastic, wire, or paper tube over all or part of a tree seedling to reduce animal damage.
Tubular- this course is "tubular", occasionally rad, but always funky!
Underburning- Prescribed burning conducted within an existing stand of trees to remove slash or manage competing vegetation
Underplanting- Planting trees beneath an existing canopy of larger trees or shrubs
Understory- Plants growing under the canopy formed by other, taller plants in a forest
Ungulates- Deer and elk.
Viability- A relative measure of the number of surviving individuals of any given phenotypic or genotypic class.
Vernacular - employing the everyday language of a people (good word for a forester to know)
Vermiculite - any of a group of platy minerals, hydrous silicates of aluminum, magnesium, and iron that expand markedly on being heated. Used in insulation and container growing media.
Water potential- The thermodynamic state of the water within a plant cell, equal to the difference in free energy per unit volume between matrically bound, pressurized, or osmotically constrained, water and that of pure water. [ha,ha...if this 'killer' definition bothers you go to xylem pressure potential.]
Weeds- Plants that are not wanted at a particular place or time
Wilting coefficient- The amount of water remaining in a soil when a plant is in a state of permanent wilting.
Wrenching - Breaking both larger and finer roots of nursery stock without removing plants from the soil. Soil is lifted up, usually by a machine, and then re-firmed around seedlings.
Xeric- Having very little moisture; tolerating or adapting to dry conditions.
Xylem water potential - A measure of xylem sap tension which is an indicator of plant water stress. Increasing negative xylem pressure potential (e.g., -0.5 MPa to -1.5 MPa) reflect increasing plant water or moisture stress in the plant.[PWP or plant water potential is a critically important concept to understand in plant sciences like forestry, botany, and ecology. Adaptability and growth of plants are highly dependent upon their genetic relationship with water.]
Yard- A derived fps unit of length equal to 0.9144m.
Zoospore- An independently motile spore in protistans, some fungi and algae.
Back to top
The unfortunate need people who will be kind to them; the prosperous need people to be kind to.