n-Tree distance sampling for per-tree estimates with application to unequal-sized cluster sampling of increment core data

2003 ◽  
Vol 33 (7) ◽  
pp. 1189-1195 ◽  
Author(s):  
Thomas B Lynch ◽  
Robert F Wittwer
Keyword(s):  
New York ◽  
Populus Deltoides ◽  
Distance Sampling ◽  
Weighted Average ◽  
Cluster Sampling ◽  
Ratio Estimator ◽  
Increment Core ◽  
Tree Distance ◽  
Plot Size ◽  
Large Trees

Samples from the n trees nearest to a point or plot center are sometimes used to estimate per-tree values such as age or growth from increment cores. Clutter et al. (J.L. Clutter, J.C. Fortson, L.V. Pienaar, G.H. Brister, and R.L. Bailey. 1983. Timber management: a quantitative approach. John Wiley & Sons, New York) indicated that this procedure can be biased because it is more likely to sample large trees occupying large amounts of space. This sampling procedure falls into the category of n-tree distance sampling in which the nth closest tree to a point defines a plot radius that can be used to estimate number of trees or amount of volume per hectare. When a ratio of n-tree per-hectare estimates is used to estimate per-tree attributes, the resulting estimator is a weighted average in which weights are the inverse of the n-tree sampling plot size. Since this ratio estimator essentially weights observations inversely with plot size, it is not subject to the objections of Clutter et al. (1983). This estimator is used to estimate age by diameter at breast height class for eastern cottonwood (Populus deltoides Bartr. ex Marsh.) on the Cimarron National Grassland.

Testing for stand dynamics effects on red spruce growth trends

1987 ◽  
Vol 17 (12) ◽  
pp. 1487-1495 ◽  
Author(s):  
Paul C. Van Deusen
Keyword(s):  
New York ◽  
Red Spruce ◽  
Stand Dynamics ◽  
Growth Data ◽  
Growth Reduction ◽  
Old Growth ◽  
Usda Forest Service ◽  
Increment Core ◽  
Second Growth ◽  
Insect Activity

Increment-core data for old-growth red spruce (Picearubens Sarg.) were collected for dendrochonological purposes and compared with second-growth data obtained from USDA Forest Service inventory plots in Maine, New Hampshire, Vermont, and New York. The research objective was to test the hypothesis suggested by J. W. Hornbeck and R. B. Smith (1985, Can. J. For. Res. 15: 1199–1201) that red spruce show reduced growth in the Northeastern United States due to stand dynamics resulting from past logging and insect activity. A graphical approach and a modeling approach based on the Kalman filter were employed. The results indicate that the growth reduction is greater in second-growth stands and that the second-growth stands are converging to an old-growth condition. This supports the stand dynamics hypothesis for second-growth stands.

Large Trees near New York City

1880 ◽  
Vol 7 (10) ◽  
pp. 107 ◽  
Author(s):  
W. H. Rudkin
Keyword(s):  
New York ◽  
New York City ◽  
York City ◽  
Large Trees

scholarly journals Effects of Post-Fire Salvage Logging on Cavity-Nesting Birds and Small Mammals in Southeastern Montana

2012 ◽  
Vol 125 (4) ◽  
pp. 316 ◽  
Author(s):  
William J. Kronland ◽  
Marco Restani
Keyword(s):  
Small Mammals ◽  
Small Mammal ◽  
Sampling Methods ◽  
Nest Survival ◽  
Distance Sampling ◽  
Salvage Treatment ◽  
Control Treatment ◽  
Salvage Logging ◽  
Cavity Nesting ◽  
Large Trees

We investigated how post-fire salvage logging of Ponderosa Pine (Pinus ponderosa) affected populations of cavity-nesting birds and small mammals in southeastern Montana in 2004 and 2005. We examined two salvage and two control plots with three point-count stations and one small mammal trap site randomly distributed across each plot. We used point counts and distance sampling methods to estimate density of cavity-nesting birds on each treatment. We also searched each plot for nests and used program MARK to construct a set of candidate models to investigate variations in nest survival related to treatment, year, and time. We used live traps arranged in webs centered on trapping sites and distance sampling methods to estimate small mammal density. Habitat characteristics were also quantified on each plot. Density of all cavity-nesting birds combined and of Hairy Woodpeckers (Picoides villosus) in particular were higher on the control than the salvage treatment. Density of large trees and abundance of active cavities were higher on the control treatment. Nest cavities on the salvage treatment were most often located in non-logged watersheds. Nest survival estimates were uniformly high, with only marginal variations attributed to treatment and year. Density of Deer Mice (Peromyscus maniculatus) was higher on the salvage than the control treatment, reflecting the amount of downed woody debris created during harvest.

Efficient statistical estimators and sampling strategies for estimating the age composition of fish

2015 ◽  
Vol 72 (6) ◽  
pp. 938-953 ◽  
Author(s):  
Sondre Aanes ◽  
Jon Helge Vølstad
Keyword(s):  
Gadus Morhua ◽  
Stock Assessment ◽  
Correlated Data ◽  
Cluster Sampling ◽  
Ratio Estimator ◽  
Sampling Strategies ◽  
Age Composition ◽  
Empirical Survey ◽  
The Common ◽  
Alternative Estimator

Estimates of age compositions of fish populations or catches that are fundamental inputs to analytical stock assessment models are generally obtained from sample surveys, and multistage cluster sampling of fish is the norm. We use simulations and extensive empirical survey data for Northeast Arctic cod (Gadus morhua) to compare the efficiency of estimators that use age–length keys (ALKs) with design-based estimators for estimating age compositions of fish. The design-based weighted ratio estimator produces the most accurate estimates for cluster-correlated data, and an alternative estimator based on a weighted ALK is equivalent under certain constraints. Using simulations to evaluate subsampling strategies, we show that otolith collections from a length-stratified subsample of one fish per 5 cm length bin (∼10 fish total) per haul or trip is sufficient and nearly as efficient as a random subsample of 20 fish. Our study also indicates that the common practice of applying fixed ALKs to length composition data can severely underestimate the variance in estimates of age compositions and that “borrowing” of ALKs developed for other gears, areas, or time periods can cause serious bias.

Effects of two silvicultural regimes with large tree retention on epiphytic macrolichen communities in Adirondack northern hardwoods, New York, USA

2007 ◽  
Vol 37 (10) ◽  
pp. 1854-1866 ◽  
Author(s):  
Heather T. Root ◽  
Gregory G. McGee ◽  
Ralph D. Nyland
Keyword(s):  
New York ◽  
Community Composition ◽  
Old Growth ◽  
Epiphytic Lichen ◽  
Tree Diameter ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
Lichen Community ◽  
Selection Systems ◽  
Large Trees

We sampled epiphytic lichen communities in nine Adirondack northern hardwood stands: three old growth, three reserve shelterwood, and three single-tree selection systems. Our objectives were to assess the effects of treatment, tree diameter at breast height, and their interaction on lichen communities and to determine whether lichen traits were associated with particular habitats. Lichen community composition was strongly related to tree diameter at breast height and differed between old growth and reserve shelterwoods. Lichen community composition was also related to an interaction between tree size and stand type. Lobaria pulmonaria (L.) Hoffm. was associated with large trees in old growth, whereas Evernia mesomorpha Nyl., Parmelia sulcata Taylor, and Physcia millegrana Degel. characterized those in shelterwood stands. Nitrophilous lichens were most common on small trees and in reserve shelterwoods, whereas small trees in selection systems and old growth supported lichens that were found to be most associated with larger trees overall. Selection systems apparently maintained lichen communities indistinguishable from those in old growth or reserve shelterwood. Because large trees hosted unique epiphyte assemblages particularly rich in fruticose and cyanolichen species, we expect that management retaining few or no large trees will alter epiphytic lichen communities.

Evaluation of n-Tree Distance Sampling for Inventory of Headwater Riparian Forests of Western Oregon

2012 ◽  
Vol 27 (3) ◽  
pp. 109-117 ◽  
Author(s):  
Zane Haxtema ◽  
Hailemariam Temesgen ◽  
Theresa Marquardt
Keyword(s):  
Distance Sampling ◽  
Riparian Forests ◽  
Tree Distance

RATIO ESTIMATOR IN ADAPTIVE CLUSTER SAMPLING BASED ON RANKED SET

2016 ◽  
Vol 49 (2) ◽  
pp. 105-116
Author(s):  
Nipaporn Chutiman ◽  
Monchaya Chiangpradit ◽  
Sujitta Suraphee
Keyword(s):  
Cluster Sampling ◽  
Ratio Estimator ◽  
Adaptive Cluster Sampling

scholarly journals Ratio Estimator in Adaptive Cluster Sampling without Replacement of Networks

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Nipaporn Chutiman ◽  
Monchaya Chiangpradit
Keyword(s):  
Auxiliary Variable ◽  
Cluster Sampling ◽  
Ratio Estimator ◽  
Adaptive Cluster Sampling ◽  
Population Total ◽  
Sampling Without Replacement ◽  
Numerical Examples ◽  
Ratio Estimators

In this paper, we study the estimators of the population total in adaptive cluster sampling by using the information of the auxiliary variable. The numerical examples showed that the ratio estimator in adaptive cluster sampling without replacement of networks is more efficient than the ratio estimators in adaptive cluster sampling without replacement of units.

Design-unbiased estimation for point-to-tree distance sampling

2006 ◽  
Vol 36 (6) ◽  
pp. 1407-1414 ◽  
Author(s):  
Christoph Kleinn ◽  
František Vilčko
Keyword(s):  
Unbiased Estimator ◽  
Distance Sampling ◽  
Spatial Arrangement ◽  
Field Application ◽  
Unbiased Estimation ◽  
Stem Density ◽  
Sample Point ◽  
Statistical Point ◽  
Tree Distance ◽  
Inclusion Zone

Point-to-tree distance sampling designs, sometimes also referred to as k-tree sampling or fixed-count sampling, are practical response design options for field sampling in forest inventories and ecological surveys. While practitioners accept and use several approaches to estimate stem density and other stand attributes, a major concern from a statistical point of view is the lack of a general unbiased estimator for this class of sampling strategies. In this paper we analyse point-to-tree distance sampling in the framework of design-based probabilistic sampling and present an unbiased estimator valid for estimation of any stand attribute. This estimator draws upon the idea of defining an inclusion zone around each tree. A tree is taken as a sample tree if a selected sample point falls into its inclusion zone. The size of the inclusion zone is therefore a measure of the individual tree's inclusion probability when sampling is done with random sample points. Once the inclusion probabilities are known for all sampled trees, the Horwitz-Thompson estimator can be used as an unbiased estimator for any stand variable. In point-to-tree distance sampling, the inclusion zone of a particular tree depends exclusively on the spatial arrangement of the neighbouring trees. Such inclusion zones are determined by k-order Voronoi polygons, where k is the number of trees being sampled per sample point. The approach, however, requires the positions of the k sample trees and a number of surrounding trees to be mapped. Field application is therefore difficult, but a comparison of plot designs by simulation studies in fully mapped stands can now also be done with an unbiased estimator for k-tree sampling.

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