Site Index Table Research Articles

Accelerating regrowth of temperate‐maritime forests due to environmental change

AbstractTo understand how environmental changes have influenced forest productivity, stemwood biomass (B) dynamics were analyzed at 1267 permanent inventory plots, covering a combined 209 ha area of unmanaged temperate‐maritime forest in southwest British Columbia, Canada. Net stemwood production (ΔB) was derived from periodic remeasurements of B collected over a 40‐year measurement period (1959–1998) in stands ranging from 20 to 150 years old. Comparison between the integrated age response of net stemwood production, ΔB(A), and the age response of stemwood biomass, B(A), suggested a 58 ± 11% increase in ΔB between the first 40 years of the chronosequence period (1859–1898) and the measurement period. To estimate extrinsic forcing on ΔB, several different candidate models were developed to remove variation explained by intrinsic factors. All models exhibited temporal bias, with positive trends in (observed minus predicted) residual ΔB ranging between of 0.40 and 0.64% yr−1. Applying the same methods to stemwood growth (G) indicated residual increases ranging from 0.43 and 0.67% yr−1. Higher trend estimates corresponded with models that included site index (SI) as a predictor, which may reflect exaggeration of the age‐decline in SI tables. Choosing a model that excluded SI, suggested that ΔB increased by 0.40 ± 0.18% yr−1, while G increased by 0.43 ± 0.12% yr−1 over the measurement period. Residual G was significantly correlated with atmospheric carbon dioxide (CO2), temperature (T), and climate moisture index (CMI). However, models driven with climate and CO2, alone, could not simultaneously explain long‐term and measurement‐period trends without additional representation of indirect effects, perhaps reflecting compound interest on direct physiological responses to environmental change. Evidence of accelerating forest regrowth highlights the value of permanent inventories to detect and understand systematic changes in forest productivity caused by environmental change.

Growth and yield models for Dahurian larch plantations

Several equations were selected using nonlinear regression analysis for setting up growth and yield models of Dahurian larch (Larix gmelinii Rupr.) plantations. Data of 405 stem analysis trees were collected from 336 temporary plots throughout the Daxing'an Mountains. Results showed that the Richards equation was the best model for estimating tree height, stand mean height and stand dominant height by age; the Power equation was the fittest model for predicting tree volume by DBH and tree height, and the Logarithmic stand volume equation was good for predicting stand volume from age, mean height, basal area and other stand variables. These models can be used to construct volume tables, site index table and other forestry tables for Dahurian plantations.

Growth models and site index table of natural Korean pine forests

According to the growth characteristics of natural Korean pine (Pinus Koraiensis) forests, 6 equations such as Chapman-Richards equation, Logistic equation, Power equation, and so on were selected to fit for the growth models for Korean pine forest. The growth models were developed based on 208 random trees and 240 dominant trees. Results show that the Chapman-Richards equation is the best model for estimating tree height by age and DBH, while the Parabola equation is fittest for predicting DBH by age or estimating age from DBH. The site index table of Korean pine forest was compiled by using the proportional method with the Chapman-Richards equation as the guide curve and validated by accuracy test.

Application of theoretical growth functions for Mongolian oak (Qurcus mongolica)

Four alternative functions are used for fitting tree height and diameter growth models for mongolian oak. (Quercus mongolica Fisch. et Turcz.). The data set includes 1250 random trees and 755 dominant trees coming from 510 temporary plots. The resultsshow that the Richards function is the best model for predicting height. diameter at breast height (DBH) and dominant height from age. The average growth curve of dominant height is used as a guide curve for the construction of a site index table which is partially validated using an independent data set. The Mitscherlich function is the best model for estimating height and dominant height from DBH.

Evaluation of site quality for dahurian larch forests

The site index table, site class table and quantizing model of dahurian larch forests were formed based on 418 temporary plots and 179 dominant stem analysis trees. By testing raw data which were not used to form the site index table, the site index table of plantations was validated. The site index table or site class table can be used in timber stands according to the intensive degrees of forest management. The quantizing model can be used in cutover, deforested and nonforested areas.

The construction of some forestry tables for dahurian larch plantations

Several growth models were selected to fit data of dahurian larch plantations using nonlinear regression analysis. The best models were used to construct the site index table, the 2-way volume table and the growth process table. The Chapman-Richards equation is the best model used as the guide curve to form the site index table for dahurian larch plantations.

The study on site quality evaluation for dahurian larch (Larix gmelinii Rupr.)

Site quality of larch (Larix gmelinii Rupr.) in Da Xingan Mountain in Inner Mongolia was studied systematically with about 1000 temporary plots and computer software. The nature of site class and site index curve was discussed in view of general mathematical model of height growth. The height growth of dominant tree of four divisions of forest stands were studied and site index tables were constructed respectively. In order to unify the comparing standard and convenience for management in this region, site index table was constucted too. Based on discussing the action and accuracy of forest type, a series of site quality evaluation (forest type-site index class-site index) was suggested.

Application of remote sensing techniques to forest site survey

Abstract A forest site survey is fundamental work for afforestation and forest management. The traditional approach to forest site survey requires a large amount of field work and is time consuming. An alternative method of classification and mapping of forest site types with remote sensing data is described in this paper. With this method, site information is extracted through remote sensing image interpretation, site conditions are classified by ordination analysis and appraised using a quantitative aerial photo site index table, which is compiled using a quantitative theory. Finally, site productivities are predicted and a site type map is mapped. The accuracies of experimental results obtained from Mt Da‐Gui forest farm, Guang Xi province, China, indicates that the remote sensing methods meet the operational standard for forest site survey.

Growth and yield models for dahurian larch plantations

Growth and yield models were developed for individual tress and stands based on 336 temporary plots with 405 stem analysis trees of dahurian larch (Larix gmelinii(Rupr.)Rupr.) plantations throughout Daxing’anling mountains. Several equations were selected using nonlinear regression analysis. Results showed that the Richards equation was the best model for estimating tree height, stand mean height and stand dominant height from age; The Power equation was the best model for prediction tree volume from DBH and tree height; The logarithmic stand volume equation was good for predicting stand volume from age, mean height, basal area and other stand variables. These models can be used to construct the volume table, the site index table and other forestry tables for dahurian larch plantations.

Northeastern Forest Survey Site Index Equations and Site Productivity Classes

Abstract The Forest Inventory and Analysis project of the Northeastern Forest Experiment Station estimates site productivity as part of its survey of the forest resources. Site productivity is defined as the growth rate of a fully stocked stand at the age of maximum mean annual increment. It is assumed that site productivity is related to site index and can be estimated from it. Polymorphic site index equations for 19 species found in the Northeast are presented for use in determining site productivity class. The equations were developed from existing site index tables or equations and are intended to facilitate the analysis of forest growth and potential productivity. North. J. Appl. For. 3:144-148, Dec. 1986.

A Lodgepole Pine Density Management Diagram

Abstract A diagram is presented that can greatly facilitate density management of lodgepole pine (Pinus contorta) stands. Together with site index tables or curves, the diagram can be used to estimate average tree sizes and total yields produced under various density management regimes. Its use is illustrated with three alternative regimes. West. J. Appl. For. 1:6-11, Jan. 1986