Abstract
Silvopastoral models require the development of the relationship between understorey pasture production, and the overstorey tree production. The Tikitere agroforestry trial, located near Rotorua in the Bay of Plenty, was established in Pinus radiata at a range of stockings in 1973, and monitored for stand parameters, understorey pasture production, and livestock carrying capacity between 1976 and 1992. A canopy closure model, developed for radiata pine plantations in the Bay of Plenty, shows a strong relationship (R2 ≈ 0.92) between canopy closure and the stand parameters of basal area and the ratio of green crown length to mean top height. Canopy closure was predicted for the Tikitere stands using the canopy closure model. A strong linear relationship (R2 ≈ 0.89) was shown to exist between the measured pasture production, and the predicted canopy closure. This indicates that direct assessment of canopy closure combined with a measurement of understorey pasture production, may be a simpler and more cost effective research technique than relying entirely on the continuous measurement of understorey pasture in the development of understorey/overstorey relationships.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Bentley CV (1996) Prediction of residual canopy cover for white pine in Central Ontario. Ontario Min. Nat. Resour., Northern Ontario Development Agreement Note No. 20, 5 pp
Daubenmire R (1959) A canopy-coverage method of vegetation analysis. NorthWest Sci 33: 43–64
Dealy EJ (1985) Tree basal area as an index of thermal cover for elk. USDA, Pacific NorthWest Experiment Station, Research Note PNW-425, 6 pp
Dunlop J (1995) Permanent sample plot system user manual. New Zealand Forest Research Institute, Rotorua, NZ. FRI Bulletin 187, 145 pp
Evans GC and Coombe DE (1959) Hemispherical and woodland canopy photography and the light climate. J Ecol 47: 103–113
Ganey JL and Block WM (1994) A comparison of two techniques for measuring canopy closure. Western J of Applied For 9(1): 21–23
Hawke MF and Gillingham AG (1997) Changes in understorey pasture composition in agroforestry regimes in New Zealand. In: Proceedings of the XVIII International Grassland Congress, June 8–19, Saskatoon, Saskatchewan, Canada, 1997
Hawke MF and O’Connor MB (1993) Soil pH and nutrient levels at Tikitere agroforestry research area. NZ J For Sci 23(1): 40–48
Horvath GC, Gordon AM and Knowles RL (1995) Characteristics of radiata pine shelterbelts that influence optical porosity and their effects on wind velocity. In: Ehrenreich JH, Ehrenreich DL and Lee HW (eds) Growing A Sustainable Future, Proceedings of the 4th North American Agroforestry Conference, Boise, Idaho, July 23–26, 1995
James FC (1971) Ordination of habitat relationships among breeding birds. Wilson Bulletin No. 83: 215–226
Johansson T (1986) Canopy density in stands of Picea abiesand Pinus sylvestrisand different thinning methods. Scand J For Res 1: 483–492
Johansson T (1996) Estimation of canopy density and irradiance in 20 to 40 year old birch stands (Betula pubescensEhrh. and Betula pendulaRoth). Trees 10: 223–230
Laymon SA (1988) The ecology of the spotted owl in the central Sierra Nevada, California. Ph.D. Diss., University of California, Berkeley, CA
Lemmon RE (1956) A spherical densiometer for estimating forest over-storey density. For Sci 2: 314–320
Maclaren JP (ed) (1988) Agroforestry symposium proceedings. New Zealand Forest Research Institute, Rotorua, NZ. FRI Bulletin 139, 299 pp
Maclaren JP (1996) Environmental effects of planted forests in New Zealand. New Zealand Forest Research Institute, Rotorua, NZ. FRI Bulletin 198, 180 pp
Mitchell JE and Popovich SJ (1996) Effectiveness of basal area for estimating canopy cover of ponderosa pine. For Eco and Mgmt 95: 45–51
Mouer M (1985) COVER: A user’s guide to the CANOPY and SHRUBS extension of the Stand Prognosis model. USDA For. Serv., Intermountain Res. Stn, General Tech. Report INT-190, 49 pp
O’Brien R and Van Hooser DD (1983) Understorey vegetation inventory: An efficient procedure. USDA For. Serv. Res. Pap. INT-323
Paton VJ (1988) Predicting the maximum area of pasture covered by radiata pine thinning and pruning slash. In: Maclaren P (ed) Agroforestry Symposium Proceedings. NZ FRI, Rotorua, NZ. FRI Bulletin 139: 130–144
Percival NS and Knowles RL (1983) Combinations of Pinus radiata and pastoral agriculture on New Zealand hill country: Agricultural productivity. In: David Hannaway (ed) Foothills for Food and Forests. Oregon State University, College of Agricultural Sciences. Symposium series no. 2: 185–202
Percival NS and Knowles RL (1988) Relationship between radiata pine and understorey pasture production. In: Maclaren P (ed) Agroforestry Symposium Proceedings. NZ FRI, Rotorua, NZ. FRI Bulletin 139: 152–160
Radcliffe JE (1974) Seasonal distribution of pasture production in New Zealand. 1. Methods of measurement. NZ J of Exp Agric 2: 337–340
Ratkowsky DA (1989) Handbook of Non-linear Regression Models. Marcel Dekker Inc, New York, NY, 241 pp
Strickler GS (1959) Use of the densiometer to estimate density of forest canopy on permanent sample plots. USDA For. Serv. Res. Note 180
West GG, Percival NS and Dean MG (1988) Oversowing legumes and grasses for forest grazing: interim research results. In: Maclaren P (ed) Agroforestry Symposium Proceedings NZ FRI, Rotorua, NZ. FRI Bulletin 139: 203–230
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Knowles, R.L., Horvath, G.C., Carter, M.A. et al. Developing a canopy closure model to predict overstorey/understorey relationships in Pinus radiata silvopastoral systems. Agroforestry Systems 43, 109–119 (1998). https://doi.org/10.1023/A:1026463623463
Issue Date:
DOI: https://doi.org/10.1023/A:1026463623463