Document Details

Site Index Models for Amabilis Fir
Nigh, Gordon D.
Amabilis fir (Abies amabilis) is a common species on the coast of British Columbia. It often occurs in complex stands, i.e., in mixtures with other species such as western hemlock or, in uneven-aged stands. Site index curves that were developed by MacMillan-Bloedel for amabilis fir are available for use in British Columbia. However, these curves were developed using old sampling protocols. As well, growth intercept models are not available and we plan on extending the range of the data for the new site index models. The purpose of this project is to develop site index and growth intercept tools for amabilis fir, and to augment the SIBEC data warehouse with data for amabilis fir. All these tools are designed to provide site index estimates. The site index models also estimate stand height. Site index is a key driver in growth and yield models such as VDYP and TIPSY, which are commonly used in British Columbia. These growth and yield models are used to formulate silviculture prescriptions and for timber supply analyses. Therefore, good site index estimates are critical for timber supply and silviculture applications. These estimates are even more important for amabilis fir given the Coast Revitalization Strategy, which is aimed at improving timber supply on the coast. We propose to execute this project according to the stem analysis standards for site index research (the only deviation from these standards are that we will only sample 50 plots due to the high cost for contractors): These standards call for 100 stem analysis plots to be established. However, due to high costs we propose to establish only 50 plots on Vancouver Island. We also propose to use the stem splitting option. Stem splitting is being used because it results in more accurate data and although it requires more field work, it may be more efficient because the handling of stem disks and ring counting are avoided. A full ecosystem classification will be done on the plots so the data will meet the SIBEC data sampling standards and be available for inclusion in the SIBEC data warehouse. The site index and growth intercept models will be incorporated into the Sindex software, which is widely used to estimate height and site index. Therefore, through this software, the models will find their way into timber supply analyses and the subsequent setting of AACs. The SIBEC data will go into the SIBEC data warehouse, where it will be included in the next analysis and approximation report. Consquently, the results will be used whenever the SIBEC site index estimates are used for amabilis fir.
Report Number
Extension Note 94: Amabilis fir height-age and growth intercept models for British Columbia
Research Report 30: Amabilis fir height-age and growth intercept models for British Columbia

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