| You are here:
Research Branch > Stand Management >
||Terminology such as "juvenile thinning", "juvenile spacing", "spacing", and "precommercial thinning" generally refers to cuttings made in immature stands with the objective of reducing stand density in order to stimulate the growth of the remaining crop. Thinning affects the size and growth of individual trees and also the growth per unit area of the stand itself. The timing and intensity of juvenile thinning has large potential impacts on the amount, size, and value of timber harvested from managed forests and on biological and technical rotation lengths. By preventing, or alleviating, height repression, juvenile thinning in extremely dense stands may provide a more reliable estimate of site potential as represented by site index.
Several long-term experimental projects (EP´s) testing a variety of species and post-thinning regimes have been established by the BC Ministry of Forests, Research Branch in coastal and interior managed forests. The earliest thinning field experiments were established on Vancouver Island in 1929. Growth and yield data from thinning experiments is a vital source of data for treatment response predictions within managed stand growth prediction models. Older EP´s also provide data for checking a model´s long-term growth trends.
Experimental Projects - Coast
Experimental Projects - Interior
Juvenile Thinning Publications
Brockley, R.P. and P. Sanborn. 2003. Effects of Sitka alder on the growth and foliar nutrition of young lodgepole pine in the central interior of British Columbia. Can. J. For. Res. 33: 1761-1771. [PDF]
Brockley, R. and P. Sanborn. 2007. Assessing the effects of Sitka alder on the growth of young lodgepole pine in the central interior of British Columbia (SBSdw3): 9-year results. B.C. Ministry of Forests and Range, Victoria. Extension Note 79.
Johnstone, W.D. 1985. Thinning lodgepole pine. In Proc. Lodgepole Pine the Species and its Management, May 8-10, 1984, Spokane, WA, and May 14-16, 1984, Vancouver, B.C. D.M. Baumgartner et al. (editors). Washington State University, Cooperative Extension, Pullman, WA. pp. 251-260.
Johnstone, W.D. 2002. Thinning lodgepole pine in southeastern British Columbia (EP 384/385): 46-year results. B.C. Ministry of Forests, Victoria. Working Paper 63.
Johnstone, W.D. 2005. The effects of juvenile spacing on 7-year-old lodgepole pine in central British Columbia. West. J. Appl. For. 20: 160-166.
Johnstone, W.D. and D.M. Cole. 1988. Thinning lodgepole pine: a research review. In Proc. Future Forests of the Mountain West: a Stand Culture Symposium, September 29 - October 3, 1986, Missoula, Montana. W.C. Schmidt (editor). U.S. Dept. of Agriculture, Forest Service, Ogden, Utah. Gen. Tech. Rep. INT-243. pp. 160-164.
Johnstone, W.D. and F. J. van Thienen. 2004. A summary of early results from recent lodgepole pine thinning experiments in the British Columbia interior. B.C. Ministry of Forests, Victoria. Technical Report 016.
Johnstone, W.D., and F.J. van Thienen. 2006. A summary of 10- to 15-year results from Douglas-fir thinning experiments in the British Columbia interior. B.C. Ministry of Forests and Range, Victoria, B.C. Technical Report 027.
Omule, S.A.Y. 1985. Response of coastal Douglas-fir to pre-commercial thinning on a medium site in British Columbia. B.C. Ministry of Forests, Victoria. Research Note 100. (EP 554)
Sanborn, P., R. Brockley, and C. Preston. 2001. Effects of Sitka alder retention and removal on the growth of young lodgepole pine in the central interior of British Columbia. B.C. Ministry of Forests, Victoria. Working Paper 60.
Thompson, C.F. 1992. Crop-tree thinning of western larch in southeastern British Columbia: 30-year results. B.C. Ministry of Forests, Victoria. Research Note No. 110.
Warrick, G. 1948. Thinning and pruning of second-growth Douglas-fir in the coastal region of British Columbia. B.C. Ministry of Forests, Victoria. Research Note 13.
Warrick, G.C. 1979. Successive thinnings in a natural stand of Douglas-fir over a fifty year period. B.C. Ministry of Forests, Victoria. Research Note 87. (EPs 62-66, 283)