Comparing performance of contrasting distance-independent and distance-dependent competition metrics in predicting individual tree diameter increment and survival within structurally-heterogeneous, mixed-species forests of Northeastern United States

Northern hardwood species display a variety of forms and defects that can reduce stem quality and complicate their timber management. However, for the most part, growth and yield models do not account for the influence of stem form and damage. This study determined the influence of stem form and damage on growth, survival, and projected future sawlog value among several northern commercial hardwood species. To accomplish this, hardwood trees on 112 permanent plots across three long-term research sites in Maine were assigned stem form and risk classes using a tree classification system developed in New Brunswick. A highly significant influence of stem form and risk on annualized individual-tree diameter increment and survival was found. Inclusion of these equations into a regional growth and yield model highlighted the importance of stem form and defects on long-term simulations as projected stand-level future value was significantly reduced by over 17%, on average (range of 13% to 28%), when compared with projections that did not include that tree-level information. The results highlight the importance of stem form and defects, as well as the need to account for them, in growth and yield applications that assess the forecasted value of commercially important hardwood stands.

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Modeling individual tree diameter increment for dipterocarpaceae and non-dipterocarpaceae in tropical rainforest

Proceedings of the 8th International Conference on Ubiquitous Information Management and Communication - ICUIMC '14 ◽

10.1145/2557977.2557992 ◽

2014 ◽

Author(s):

Nurashikin Saaludin ◽

Yasmin Yahya ◽

Suriyati Harun ◽

Wan Suriyani Che Wan Ahmad

Keyword(s):

Tropical Rainforest ◽

Individual Tree ◽

Tree Diameter ◽

Diameter Increment

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An individual tree diameter increment model for white spruce in Alberta

Canadian Journal of Forest Research ◽

10.1139/x95-158 ◽

1995 ◽

Vol 25 (9) ◽

pp. 1455-1465 ◽

Cited By ~ 33

Author(s):

Shongming Huang ◽

Stephen J. Titus

Keyword(s):

White Spruce ◽

Model Parameters ◽

Data Set ◽

Individual Tree ◽

Error Structure ◽

Permanent Sample Plots ◽

Tree Diameter ◽

Diameter Increment ◽

Diameter Increment Model ◽

Age Independent

Based on a data set from 164 permanent sample plots, an age-independent individual tree diameter increment model is presented for white spruce (Piceaglauca (Moench) Voss) grown in the boreal mixed-species stands in Alberta. The model is age independent in that it does not explicitly require tree or stand age as input variables. Periodic diameter increment is modelled as a function of tree diameter at breast height, total tree height, relative competitiveness of the tree in the stand, species composition, stand density, and site productivity. Because data from permanent sample plots are considered time series and cross sectional, diagnostic techniques were applied to identify the model's error structure. Appropriate fit based on the identified error structure was accomplished using weighted nonlinear least squares with a first-order autoregressive process. Results show that (1) all model parameters are significant at α = 0.05 level, and (2) the plot of studentized residuals against predicted diameter increment shows no consistent underestimate or overestimate for diameter increment. The model was also tested on an independent data set representing the population on which it is to be used. Results show that the average prediction biases are not significant at α = 0.05 level, indicating that the model appropriately describes the data and performs well when predictions are made.

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Rapid Assessment of Relative Density in Mixed-Species Stands of the Northeastern United States

International Journal of Forestry Research ◽

10.1155/2010/212068 ◽

2010 ◽

Vol 2010 ◽

pp. 1-8

Author(s):

M. J. Ducey ◽

R. A. Knapp

Keyword(s):

United States ◽

Specific Gravity ◽

Rapid Assessment ◽

Basal Area ◽

Stand Density ◽

Sampling Technique ◽

Northeastern United States ◽

Mixed Species ◽

Stand Density Index ◽

Simple Tree

Basal area has shortcomings as a measure of stand density, but it is often preferred for operational assessments because it is easy to measure. Previous work has demonstrated that an additive version of Reineke's stand density index can be estimated by a simple tree count using a modified horizontal point sampling technique. We show that this technique can be extended further to estimate a mixed-species density measure that has been developed for complex stands in the northeastern United States, using wood specific gravity to harmonize the density contributions of different species. The sampling technique provides design-unbiased estimates of stand density from a weighted tree count, where the weights depend on specific gravity but not on diameter. Rounding the specific gravity values for different species in the calculation of estimates introduces a trivial amount of bias but streamlines the procedure for rapid use in the field.

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Individual Tree Volume Equations for the Northeastern United States: Evaluation and New Form Quotient Board Foot Equations1

Northern Journal of Applied Forestry ◽

10.1093/njaf/6.1.27 ◽

1989 ◽

Vol 6 (1) ◽

pp. 27-31 ◽

Cited By ~ 3

Author(s):

Thomas E. Burk ◽

Richard P. Hans ◽

Eric H. Wharton

Keyword(s):

United States ◽

Northeastern United States ◽

Individual Tree ◽

Tree Form ◽

Forest Survey ◽

Species Groups ◽

New Form ◽

Using Data ◽

Volume Equations

Abstract Volume equations used in forest survey in the northeastern United States were evaluated using data collected as part of utilization studies. Results are presented for both cubic foot and board foot equations for 16 species groups. Existing cubic foot equations were found to be satisfactory while the board foot equations generally produced significantly large underestimates. New board foot equations that include a measure of tree form were derived. North. J. Appl. For. 6(1):27-31, March 1989.

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