Height development of Scots pine on peatlands: describing change in site productivity with a site index model

2004 ◽  
Vol 34 (5) ◽  
pp. 1081-1092 ◽  
Author(s):  
Hannu Hökkä ◽  
Risto Ojansuu
Keyword(s):  
Scots Pine ◽  
Site Index ◽  
Stand Age ◽  
Variance Component Model ◽  
Moderate Increase ◽  
Site Productivity ◽  
Permanent Sample Plots ◽  
Index Model ◽  
Site Water ◽  
Site Index Model

The effect of site properties and forest drainage on the dominant height development of Scots pine (Pinus sylvestris L.) stands in peatland sites was studied using data from permanent sample plots located in natural and drained sites in northern Finland. The Korf model was used to describe the height development of dominant trees in natural sites. The effect of drainage on height development was accounted for by a term giving a nonlinear height increase for drained sites as a function of the time elapsed since drainage. The variance component model was applied to account for the hierarchical data structure. Natural height development after 30 years of age at DBH was significantly slower in PF sites (sparsely forested pine fens) than in PS sites (genuine forested pine swamps). Within PF sites, there were further differences in relation to nutrient availability. Temperature sum explained the variation in the intercept. In PS sites, drainage resulted in a moderate increase in the maximum attainable height, while in PF sites, drainage improved site productivity by 80%–85% in terms of the attainable height. The asymptote for drained stands was dependent on stand age at the time of drainage. Differences between the two major groups were assumed to be due to initial differences in site water regime.

scholarly journals Variable stocking yield functions for the boreal mixedwood in Ontario

1996 ◽  
Vol 72 (4) ◽  
pp. 416-419 ◽  
Author(s):  
Bijan Payandeh ◽  
Yonghe Wang
Keyword(s):  
Basal Area ◽  
Site Index ◽  
Eastern United States ◽  
Site Productivity ◽  
Area Index ◽  
Permanent Sample Plots ◽  
Index Model ◽  
Index Site ◽  
Yield Functions ◽  
Site Index Model

A measure of utilized site productivity, "basal area index" was recently developed and used to construct variable stocking yield functions and tables for the boreal mixedwood of northcentral Ontario. Data from 197 permanent sample plots supplied by the James River/Marathon Paper Company Ltd. were used. The resulting yield equations compare favourably with previous ones and are more appropriate for the boreal mixedwood. In addition, the basal area index employed has several advantages: 1) it serves as a valid measure of utilized site productivity which is better correlated with the main stand attributes than site index; 2) it produces variable stocking yield tables suitable for uneven-aged mixed species cover types; 3) unlike the site index, the basal area index may be estimated quickly, easily and inexpensively. The basic improvement in mixedwood yield estimation via basal area index should have broad applications for other stand types particularly for the disturbed hardwoods of southern Ontario and those in eastern United States. Key words: Basal area index, site index model, numerical method

A calibrateable site index model for Pinus kesiya plantations in southeastern Africa

2002 ◽  
Vol 32 (11) ◽  
pp. 1916-1928 ◽  
Author(s):  
Kalle Eerikäinen ◽  
Danaza Mabvurira ◽  
Ladislaus Nshubemuki ◽  
Jussi Saramäki
Keyword(s):  
Random Parameter ◽  
Site Index ◽  
Stand Age ◽  
Random Parameters ◽  
Index Model ◽  
Forest Inventories ◽  
Pinus Kesiya ◽  
Dominant Height ◽  
Random Parameter Model ◽  
Site Index Model

The aim of the study was to develop a site index model for Pinus kesiya Royle ex Gordon plantations in southeastern Africa based on the relationship between the dominant height and stand age. Conversely, analysis of dominant height and age data showed that the growth patterns of plantations were different. In addition, the asymptotes and forms of standwise dominant height curves varied within plantations. In developing a common site index model, instead of using the more common approach of estimating separate dominant height–age models for different plantations or sites, a mean curve approach based on a linear random parameter model with fixed and random parameters was applied. The random parameter model of this study was calibrated by predicting random parameters for the plantation and stand effects, in accordance with the standard linear prediction theory. The analyses showed that the calibration of the dominant height model was an efficient method to obtain reliable dominant height predictions of a stand, particularly when several dominant height–age observations from different stands of a plantation and at least one measured dominant height and stand age of a target stand are available. This is the case in many forest inventories based on temporary samples, i.e., cross-sectional data. The new site index model is a useful tool for use in different mensurational applications, and its properties can efficiently be utilized for example in forest inventories of P. kesiya plantations in southeastern Africa.

scholarly journals Implications of Reduced Stand Density on Tree Growth and Drought Susceptibility: A Study of Three Species under Varying Climate

Forests ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 627
Author(s):  
Mathias Steckel ◽  
W. Keith Moser ◽  
Miren del Río ◽  
Hans Pretzsch
Keyword(s):  
Scots Pine ◽  
Tree Growth ◽  
Water Availability ◽  
Ponderosa Pine ◽  
Stand Density ◽  
Stand Age ◽  
Short Term ◽  
Sessile Oak ◽  
Site Water ◽  
Positive Effect

A higher frequency of increasingly severe droughts highlights the need for short-term measures to adapt existing forests to climate change. The maintenance of reduced stand densities has been proposed as a promising silvicultural tool for mitigating drought stress. However, the relationship between stand density and tree drought susceptibility remains poorly understood, especially across ecological gradients. Here, we analysed the effect of reduced stand density on tree growth and growth sensitivity, as well as on short-term drought responses (resistance, recovery, and resilience) of Scots pine (Pinus sylvestris L.), sessile oak (Quercus petraea (Matt.) Liebl.), and ponderosa pine (Pinus ponderosa Douglas ex C. Lawson). Tree ring series from 409 trees, growing in stands of varying stand density, were analysed at sites with different water availability. For all species, mean tree growth was significantly higher under low compared with maximum stand density. Mean tree growth sensitivity of Scots pine was significantly higher under low compared with moderate and maximum stand density, while growth sensitivity of ponderosa pine peaked under maximum stand density. Recovery and resilience of Scots pine, as well as recovery of sessile oak and ponderosa pine, decreased with increasing stand density. In contrast, resistance and resilience of ponderosa pine significantly increased with increasing stand density. Higher site water availability was associated with significantly reduced drought response indices of Scots pine and sessile oak in general, except for resistance of oak. In ponderosa pine, higher site water availability significantly lessened recovery. Higher site water availability significantly moderated the positive effect of reduced stand density on drought responses. Stand age had a significantly positive effect on the resistance of Scots pine and a negative effect on recovery of sessile oak. We discuss potential causes for the observed response patterns, derive implications for adaptive forest management, and make recommendations for further research in this field.

scholarly journals SITE QUALITY ESTIMATIONS BASED ON THE GENERALIZED ALGEBRAIC DIFFERENCE APPROACH: A CASE STUDY IN ÇANKIRI FORESTS

2018 ◽  
Vol 42 (3) ◽  
Author(s):  
Ugur Akbas ◽  
Muammer SENYURT
Keyword(s):  
Site Index ◽  
Site Quality ◽  
Model Parameters ◽  
Successful Model ◽  
Index Model ◽  
Prediction Technique ◽  
Algebraic Difference ◽  
Pine Stands ◽  
Site Index Model ◽  
Generalized Algebraic Difference Approach

ABSTRACT In this study, it is aimed that the dynamic site index models were developed for Crimean Pine stands in Sarikaya-Cankiri forests located in middle northern Turkey. The data for this study are 153 sample trees obtained from the Crimean Pine stands. In modeling relationships between height and age of dominant or co-dominant trees, some dynamic site index equations such as Chapman-Richards (M1, M2, M3), Lundqvist (M4 and M6), Hossfeld (M5), Weibull (M7) and Schumacher (M8) based on the Generalized Algebraic Difference Approach (GADA) were used. The estimations for these eight-dynamic site index model parameters with well as various statistical values were obtained using the nonlinear regression technique. Among these equations, the Chapman-Richards’s equation, M3, was determined to be the most successful model, with accounted for 89.03 % of the total variance in height-age relationships with MSE: 1.7633, RMSE: 1.3279, SSE: 1165.6, Bias: -0.0380. After determination of the best predictive model, ARMA (1, 1) autoregressive prediction technique was used to account autocorrelation problems for time-series height measurements. When ARMA autoregressive prediction technique was applied to the Chapman-Richards function for solving autocorrelation problem, these success statistics were improved as SSE: 868.7, MSE: 1.3183, RMSE: 1.1482, Bias: -0.06369, R2: 0.918. Also, Durbin-Watson statistics displayed that autocorrelation problem was solved by the use of ARMA autoregressive prediction technique; DW test value=1.99, DW<P=0.5622, DW>P=0.4378. The dynamic site index model that was developed has provided results compatible with the growth characteristics expected in the modeling of height-age relations, such as polymorphism, multiple asymptote, and base-age invariance.

Development of Site Index Model for Styrax japonica

2019 ◽  
Vol 53 (4) ◽  
pp. 13-18
Author(s):  
Joon Hyung Park ◽  
◽  
Kwang Soo Lee ◽  
Yeong Mo Sonk ◽  
Su Young Jung ◽  
...  
Keyword(s):  
Site Index ◽  
Index Model ◽  
Site Index Model ◽  
Styrax Japonica

scholarly journals A system for estimating height and site index of western hemlock in the interior of British Columbia

1998 ◽  
Vol 74 (4) ◽  
pp. 588-596 ◽  
Author(s):  
Gordon D. Nigh
Keyword(s):  
British Columbia ◽  
Site Index ◽  
Tsuga Heterophylla ◽  
Western Hemlock ◽  
Index Model ◽  
Breast Height ◽  
Age Model ◽  
Site Index Model ◽  
Growth Intercept ◽  
Height Model

The focus of recent site productivity research in British Columbia has been to develop height-breast height age, growth intercept, and ecosystem-site index models. These models, together with a years-to-breast-height model, form a system for estimating site index and height. This system is described for western hemlock (Tsuga heterophylla (Raf.) Sarg.) in the interior of British Columbia. Forty-four western hemlock stem analysis plots were used in the construction of this system. As there are three models for estimating site index, the appropriate model for a given stand depends largely on the stand condition and the precision of the models. A graph of model precision against breast height age gives some assistance in deciding which model should be used to estimate site index. Key words: western hemlock, site index, height-age model, growth intercept model, years-to-breast-height model, ecosystem-site index model, model precision

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