GENGYM: A variable density stand table projection system calibrated for mixed conifer and ponderosa pine stands in the Southwest

Edminster, Carleton B.; Mowrer, H. Todd; Mathiasen, Robert L.; Schuler, Thomas M.; Olsen, W. K.; Hawksworth, Frank G.

doi:10.2737/rm-rp-297

Cited by 10 publications

(1 citation statement)

References 9 publications

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“…To determine if our projections differed substantially from those derived from a growth and yield model, we compared the predictions from the straightline projections to those of GENGYM. GENGYM is a computerized growth and yield model used for projecting future stand conditions in ponderosa pine stands (Edminster et al 1990). GENGYM supercedes RMYLD, which was used by Schmid (1987) to estimate the time for stands in the Brownsville plots to reach susceptibility thresholds.…”

Section: Methodsmentioning

confidence: 99%

Growth of ponderosa pine stands in relation to mountain pine beetle susceptibility

Obedzinski¹,

Schmid²,

Mata³

et al. 1999

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Ten-year diameter and basal area growth were determined for partially cut stands at 4 locations. Average diameters in the partially cut plots generally increased by 1 inch or more, while average diameter in the uncut controls increased by 0.9 inches or less. Individual tree growth is discussed in relation to potential susceptibility to mountain pine beetle infestation. Basal area increases ranged from 0.9 to 1.9 ft2/acre/ yr in partially cut plots, while basal area increases in the control plots ranged from 0.4 to 1.4 ft2/acre/yr. Endemic mountain pine beetle infestations and snow breakage accounted for most of the mortality on the plots, which decreased the residual basal area and basal area growth. Increases in basal area are used to estimate the length of time required for various stand densities to reach the susceptibility thresholds for mountain pine beetle infestation. Stand marking may influence future susceptibility to beetle infestations.

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Section: Methodsmentioning

confidence: 99%

Growth of ponderosa pine stands in relation to mountain pine beetle susceptibility

Obedzinski¹,

Schmid²,

Mata³

et al. 1999

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Modeling diameter growth for pinyon and juniper trees in dryland forests

Chojnacky

1997

Forest Ecology and Management

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Evaluating the Accuracy of Ground-Based Hemlock Dwarf Mistletoe Rating: A Case Study Using the Wind River Canopy Crane

Shaw

Freeman

Mathiasen

2000

Western Journal of Applied Forestry

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The accuracy of ground based estimates using the six-class dwarf mistletoe rating system was evaluated in an old-growth Douglas-fir/western hemlock forest by comparing ground ratings by five different observers to an examination of tree crowns from a construction crane at the Wind River Canopy Crane Research Facility, Washington. A total of 139 dominant, codominant, and intermediate western hemlock were evaluated. No consistent pattern emerged to indicate where overall error was made. All but one observer was relatively accurate at identifying noninfected trees (73 to 95% noninfected trees accurately rated by four observers). However, the observers were less accurate at estimating the DMR class of the infected trees (11% to 3 7% of the infected trees accurately rated), including a number of trees incorrectly rated by two or more DMR classes. One observer rated 98% of the trees as having infections, while the crane survey estimated only 53% of the trees as having infections. Each observer divided the individual tree crowns into thirds and estimated infections based on summing lower, middle, and upper canopy levels. There was no pattern to the errors associated with estimates by canopy level. One observer significantly overestimated all canopy levels, one observer estimated all accurately, one observer significantly underestimated all canopy levels, one observer underestimated the mid and upper canopies, and one observer underestimated the lower and upper canopies. The principal reasons for inaccurate dwarf mistletoe ratings were assumed to be difficulty in accurately estimating crown thirds, misidentification of infections because of various stem deformities or accumulation of organic debris resembling infections, and the difficulty in observing infections high above the ground and through dense vegetation. Only one of the five observers accurately represented the spatial pattern of the infection center. The implications of this research vary depending on whether the results are to be used for timber management or for research and modeling applications. West. J. Appl. For. 15(1):8-14.

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GENGYM: A variable density stand table projection system calibrated for mixed conifer and ponderosa pine stands in the Southwest

Cited by 10 publications

References 9 publications

Growth of ponderosa pine stands in relation to mountain pine beetle susceptibility

Growth of ponderosa pine stands in relation to mountain pine beetle susceptibility

Modeling diameter growth for pinyon and juniper trees in dryland forests

Evaluating the Accuracy of Ground-Based Hemlock Dwarf Mistletoe Rating: A Case Study Using the Wind River Canopy Crane

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