Terms - Silvicultural Terms in Canada
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


a -3/2 power law of self-thinning [relation à  la puissance -3/2 de l'éclaircie naturelle (n.f.)]
Dense populations that have reached a size at which mortality occurs demonstrate a negative relationship between log mean plant weight and log stand density; this generally has a slope of -3/2.


T-notching [tolérance (n.f.)]
The ability of an organism or biological process to subsist under a given set of environmental conditions. The range of these under which it can subsist, representing its limits of tolerance, is termed its ecological amplitude. For trees, the tolerance of most practical importance is their ability to grow satisfactorily in the shade of and in competition with other trees. (3)

cf. shade tolerance


taungya plantation [plantation en taungya (n.f.)]
The raising of a forest crop in conjunction with a temporary agricultural crop.


tending [soins culturaux (n.m.)]
Generally, any operation carried out for the benefit of a forest crop or an individual thereof, at any stage of its life; covers operations both on the crop itself, e.g., thinnings and improvement cuttings, and on competing vegetation, e.g., weeding, cleaning, and girdling of unwanted growth, but not regeneration cuttings or site preparation. (3)

cf. intermediate treatments


tending felling [coupe d'entretien (n.f.)]
An operation comprising cleanings and thinnings. (3)


thicket [fourré (n.m.)]
A dense growth of small trees or bushes. (3)


thicket stage [stade de fourré (n.m.)]
see stand development


thinning [éclaircie (n.f.)]
A cutting made in an immature crop or stand primarily to accelerate diameter increment but also, by suitable selection, to improve the average form of the trees that remain. (3)
Defined in Nova Scotia as a spacing operation designed within commercial thinning to recover potential mortality and to improve growth, quality, and percentage of desirable trees.

chemical thinning [éclaircie chimique]: Any thinning in which the unwanted trees are killed by treatment with herbicide. (3)

commercial thinning [éclaircie commercialisable]: A thinning in which harvested trees are removed from the site and used for commercial purposes. (1)

crown thinning [éclaircie par le haut]: The removal of trees from the dominant and codominant crown classes to favor the best trees of those same crown classes. (1)

Defined in Nova Scotia as the removal of trees from the dominant and codominant crown classes to promote the growth of desirable trees and species.

free thinning [éclaircie libre]: The removal of trees to control stand spacing and favor desired trees using a combination of thinning criteria without regard to crown position. (1)

low thinning [éclaircie par le bas]: The removal of trees from the lower crown classes to favor those in the upper crown classes. (1)

mechanical thinning [éclaircie systématique]: Thinning involving removal of trees in rows or strips, or by using fixed spacing intervals. (1)

precommercial thinning (PCT) [éclaircie précommerciale]: A thinning that does not yield trees of commercial value, usually designed to improve crop spacing. (1)

row thinning [éclaircie en rangée]: A thinning generally in plantations in which the trees are cut out in lines or narrow strips at fixed intervals throughout a stand. (5)

selection thinning [éclaircie jardinatoire]: The removal of trees in the dominant crown class in order to favor trees in the lower crown classes. (1)

selective thinning [éclaircie sélective]: A thinning in which trees are removed or retained on their individual merits. (16)

spacing [éclaircie par espacement]: A thinning in which trees at fixed intervals of distance are chosen for retention and all others are cut. (5)


thinning cycle [cycle d'éclaircie (n.m.)]
The time interval between thinnings in the same stand. (1)


thinning frequency [périodicité des éclaircies (n.f.)]
see thinning cycle


thinning from above [éclaircie par le haut (n.f.)]
see thinning: crown


thinning from below [éclaircie par le bas (n.f.)]
see thinning: low


thinning grade [intensité d'éclaircie (n.f.)]
A measure of the combined effect of thinning weight and thinning frequency, in terms of the volume removed during any succession of thinnings, sometimes expressed as an average annual stand depletion by dividing their total thinning weight by the number of years they cover. (3)


thinning interval [cycle d'éclaircies (n.m.)]
see thinning cycle


thinning out [dépressage (n.m.)]
Removal of seedling or sapling in excess in a young stand in order to favor residual tree development.


thinning regime [système d'éclaircie (n.m.)]
A term comprising the type, degree, and frequency of thinning for a given area, generally along with the year of commencement and sometimes termination. (3)


thinning schedule (table) [règlement d'éclaircies (n.m.)]
see thinning regime


thinning series [groupe d'éclaircies comparées (n.m.)]
Two or more adjacent forest plots that are thinned differently (e.g., to different thinning grades), essentially so as to compare the increment of individual stems. (3)


thinning weight [intensité du passage en éclaircie (n.f.)]
A degree of thinning expressed in terms of the volume removed at any one time. (3)


tie ridge [cloisonnement (n.m.)]
In contour furrowing and trenching, a narrow strip of ground left unexcavated so as to break the horizontal continuity of the trenching and thus contain and properly distribute any precipitation. (3)


timber [bois (n.m.)]
A general term for forest crops and stands, and sometimes for any lesser aggregation of such trees. (3)


timber marking [martelage (n.m.)]
see tree marking


timber stand [peuplement forestier (n.m.)]
see timber


timber stand improvement (TSI) [opération d'amélioration (n.f.)]
A term comprising all intermediate treatments made to improve the composition, structure, condition, and increment of either an even- or uneven-aged stand. (1)


tine cultivator [cultivateur à éperon (n.m.)]
see tine plough


tine harrow [herse à  éperon (n.f.)]
see tine plough


tine plough [charrue à  éperon (n.f.)]
A plough in which the leading edge of the landside is extended forward and downward as a tine-bearing replaceable sock. (3)


tissue culture [culture de tissus (n.f.)]
A general term for the cultivation of plant or animal tissues in a controlled artificial environment on defined media under aseptic conditions.


top dressing [préparation du sol superficiel (n.f.)]
Surface application of fertilizers or organic ameliorants to crops after establishment or onto land after physical preparation for planting.


top pruning [élagage des branches supérieures (n.m.)]
see pruning: high


trainer [dominé élagueur (n.m.)]
A tree beneath the main canopy which by its shading and/or abrasive action hastens the natural pruning or improves the form of some other tree. (1)


transplant [plant repiqué (n.m.)]
A seedling that has been replanted one or more times in a nursery to improve its size and growth potential characteristics. Also a tree that is moved from one place to another. (1)


transplanter [repiqueuse (n.f.)]
see transplanting machine


transplanting [repiquage (n.m.)]
An operation consisting of moving the nursery stock from one part of a nursery to another, essentially so as to improve its root development before forest planting. (3)


transplanting board [planche à  repiquer (n.f.)]
A simple device having regularly spaced slots for the individual plants so as to ensure proper spacing and lining out in the new bed. (3)


transplanting machine [repiqueuse mécanique (n.f.)]
An implement used to line out transplants in a nursery.


transplanting plough [charrue planteuse (n.f.)]
A plough used in the nursery to open trench for the roots of plants being lined out, while simultaneously backfilling it. (3)


tree breeding [amélioration génétique (n.f.)]
see forest tree breeding


tree class [classe d'arbres (n.f.)]
Any class into which the trees forming a crop or stand may be divided for a variety of purposes. (3)


tree improvement [amélioration des arbres (n.f.)]
see forest tree improvement


tree injection [injection d'arbres (n.f.)]
The deliberate introduction, by pressure or simple absorption of a chemical -- generally a water-soluble salt in solution -- into the sapstream of a living tree. (3)


tree injector [injecteur (n.m.)]
A specially designed tool used to inject a solution into a living tree.


tree marking [marquage (n.m.)]
Selection and indication, usually by marking with paint on the stem, of trees to be felled or retained.


tree nursery [pépinière (n.f.)]
see nursery


tree planter [planteuse d'arbres (n.f.)]
see planting machine


tree shaker [secoueuse mécanique (n.f.)]
A machine designed to shake a tree in order to dislodge its fruits for collection from the ground.


tree spade [pelle hydraulique à  arbres (n.f.)]
Hydraulic accessory attached to a machine used for transplanting landscape stock.


tree surgery [chirurgie des arbres (n.f.)]
The care and repair of trees valued for amenity. (3)


tree-planting machine [planteuse d'arbres (n.f.)]
see planting machine


trench planting [plantation en sillon (n.f.)]
Setting out young trees in a shallow trench or a continuous slit. (3)


trencher [soc planteur (n.m.)]
In a planting machine, a metal shoe behind the share, which makes the trench for the plant roots. (3)


trenching [scarifiage par sillons (n.m.)]
Site preparation technique creating a more or less continuous furrow, with surface debris, duff, and low vegetation scattered to one side, using shaping devices pulled or often hydraulically powered by a prime mover. (21) Commonly referred to as disc trenching in eastern Canada.


trimming [émondage (n.m.)]
Removing the side buds and side shoots from a young plant. Cutting a felled or fallen and sometimes a standing stem clear of branches and stubs. (3)


tube planting [plantation de semis en tube (n.f.)]
Setting out young trees in narrow, open-ended cylinders of various materials, in which they have been raised from seed or into which they have been transplanted. (3)


tubed seedling [semis en tube (n.m.)]
see seedling: container


two-aged stand [peuplement à  deux classes d'âge (n.m.)]
A stand containing two distinct age classes differing by more than 20% of the rotation age. (1)


two-furrow plough [charrue à  deux socs et versoirs simultanés (n.f.)]
A plough with two moldboards turning the furrow slices to the same side. (3)


two-rotation coppice system [taillis composé (n.m.)]
see coppice-of-two-rotations method


two-stage cutting (felling) [coupe en deux abattages (n.f.)]
see shelterwood cutting


two-storied high-forest system [traitement en futaie à  deux étages (n.m.)]
An accessory system in which a crop of a different species is introduced (i.e., artificially) beneath an existing immature crop, the two crops eventually being harvested together, or the upper one before the lower. (3)


two-storied stand [peuplement à  deux étages (n.m.)]
A forest stand in which two height classes of considerable difference occur, the overstory and understory. The term is not applicable to a forest in process of reproduction, in which the appearance of two stories is due to a seed tree or shelterwood cut before final cut.


        Terms in the glossary are arranged alphabetically. In some instances, terms within a family (for example, thinning) are grouped together to make it easier for the reader to compare them. In such cases, each member of a family (for example, precommercial thinning) is also listed alphabetically, but the reader is referred to the family name.

        Each term appears in boldface letters and is followed by its equivalent term in French in brackets. Terms used as both nouns and verbs are identified as such by n and v, respectively. The generic of the French equivalent term is offered in this edition, and refers to the dominant noun when the equivalent is not a single word.

        The number in parentheses following a term refers to the source of the definition. These sources are listed below. In many cases, definitions taken from such sources have been paraphrased and/or edited to agree with house style. This publication is the source of those definitions not followed by numbers in parentheses.

1. Adams, D.L., et al. 1989. Recommended changes in silviculture terminology. Unpublished. Silviculture Instructors Subgroup, Silviculture Working Group (D2), Society of American Foresters. Washington, DC.

2. Crcha, J.; Martel, J.; Savard, J. 1977. Normes de traitements sylvicoles. Ministère de l’Énergie et des Ressources, Québec.

3. Ford-Robertson, F.C. 1971. Terminology of forest science, technology practice and products. Society of American Foresters, Washington, DC.

4. Forestry Statistics and Systems Branch, Canadian Forestry Service. 1984. Reporting and summarizing forestry change data—Manitoba pilot study. Petawawa National Forestry Institute, Chalk River, Ont. Inf. Rep. PI-X-36.

5. Haddon, B.D., editor. 1988. Forest inventory terms in Canada. 3rd ed. Canadian Forest Inventory Committee, Forestry Canada.

6. Merrill, D.F.; Alexander, M.E., editors. 1987. Glossary of forest fire management terms. 4th ed. National Research Council of Canada, Canadian Committee on Forest Fire Management, Ottawa. Publication NRCC No. 26516.

7. New Brunswick Department of Natural Resources. No date. Glossary of terms.

8. Ontario Ministry of Natural Resources. 1984. Glossary of terms. Unpublished.

9. Province of Saskatchewan. 1989. Silviculture definitions. Unpublished.

10. Smith, D.M. 1986. The practice of silviculture. 8th ed. John Wiley & Sons, New York.

11. Wright, J.W. 1976. Introduction to forest genetics. Academic Press, New York.

12. Zobel, B.; Talbert, J. 1984. Applied forest tree improvement. John Wiley & Sons, New York.

Sources Added to Second Edition

13. Agriculture Handbook No. 553. U.S. Department of Agriculture. Washington, DC.

14. Holmes, S. 1979. S. Henderson’s dictionary of biological terms. 9th ed. Longman Group Ltd., London.

15. Zumer-Linder, M. 1979. Environmental word-list. Ecological Studies 3. Swedish University of Agriculture Sciences, International Rural Development Centre, Uppsala, Sweden.

16. Forestry Commission Leaflet No. 77. Oxford, UK.

17. Dawkins, H.C. 1958. The management of natural tropical high forest with special reference to Uganda. p. 127–129 in Inst. Paper No. 34, Int. For. Inst., Oxford, UK.

18. Moore, R.; Mills, T. 1977. An environmental guide to Western surface mining. Part two: Impacts, mitigation and monitoring, p. VI.1-VI.9. Fish and Wildlife Service, U.S. Department of the Interior.

19. 1974. A glossary of terms used in range management. 2nd ed. Society for Range Management, Denver, CO.

20. Collocott, T.C. (Ed.). 1971. Dictionary of science and technology. W. & R. Chambers Ltd., Edinburgh.

21. Forest Engineering Research Institute of Canada. 1993. Personal communications.

22. Winters, R.K. (Ed.). 1977. Terminology of forest science, technology, practice and products. English-language version. Addendum 1. Soc. Am. For., Washington, DC.

23. Sutton, R.F.; Tinus, R.W. 1983. Root and root system terminology. Forest Science Monograph No. 24. For. Sci. 29 (Suppl.).

24. Franzese, M.L.; Thompson, T.J.; McNutt, J. 1978. Comp. glossary of forestry related terms. Potlach Corporation, Lewiston.

25. Snyder, E.B. 1972. Glossary for forest tree improvement workers. Southern For. Exp. Stn., For. Serv., US Dep. Agr. 22  p.

26. Steppler, H.A.; Nair, P.K.R. 1987. Agroforestry: A decade of development. ICRAF, Nairobi, Kenya. 276 p.

27. Sutton, R.F. 1985. Vegetation management in Canadian forestry. Govt. Can., Can. For. Serv. Sault-Ste-Marie, Ont. Inf  Rep. O-X-369. 34 p. + Append.

28. Ontario Ministry of Natural Ressources. 1987. Timber management guidelines for the protection of tourism values.

29. Thompson, A.J.; Fleming, R. 1991. Legislative and policy limits to successful integrated pest management in Canada’s forest. For. Chron. 67(5):493-499.