不列颠·哥伦比亚省北部小杆松及白云杉立地指数与生态立地质量的关系

为在ＰｒｉｎｃｅＲｕｐｅｒｔ林区的“亚北方”部分建立生态立地质量与森林生产力的联系，对从９３个小杆松林分和７７个白云杉林分获得的数据进行了分析．所研究的林分处于两个气候状况、８个土壤水分状况以及５个土壤养分状况．这些气候、土壤水分和养分状况被视为等级变量用于林地分类和回归分析．小杆松和白云杉的立地指数随土壤水分和养分状况变化而变化，但不依赖于气候变化．与土壤水分相关的变化格局对两个种来说很相似，但与土壤养分相关的变化格局则全然不同．在所建立的５类回归模型中，土壤小区模型对于两个种都显示出立地指数与土壤水分和养分状况具有很强的相互关系（Ｒ２＞０．８０，ＳＥＥ≤１．６ｍ）．可以认为土壤水分和养分的等级度量在大范围内可作为小杆松和白云杉立地指数的预测预报因子．

Relationships between ecological site quality and site index of lodgepole pine and white spruce in Northern British Columbia

To establish a link between ecological site quality and forest productivity in the'sub--boreal'portion of the Prince Rupert Forest Region,site index and site quality data from 93 lodepole pine stands and 77 white spruce stands were obtained and analyzed.The study stands were distributed across two climatic regimes(biogeoclimatic subzones),eight soil moisture regimes,and five soil nutrient regimes.These regimes were used as categorical variables in stratification of the stands and regression analysis.Site index of lodgepole pine and white spruce changed with soil moisture and nutrient regimes but not with climate.The pattern of change in relation to sol]moisture was similar for both species but different in relation to soil nitrogen.Compared to lodgepole pine,site index of white spruce was lower on water-deficient,water-surplus,and nitrogen-deficient(very Poor,poor f and medium)sites but the same or higher within the slightly dry to very moist and rich to very rich edatopic region. Of the five types of regression models developed,the edatope model showed strong relationships between site index and soil moisture and nutrient regimes[R'>0.80,SEE(standard error of estimates)<1.6 mj for both lodgepole pine and white spruce.This model was used to construe site index isolines which were superimposed onto edatopic grids.It was concluded that the categorical measures of soil moisture and soil nutrients are good predictors of lodgepole pine and white spruce site index over a large area.