montane forest

The Role of Disturbance, Topography, and Forest Structure in the Development of a Montane Forest Landscape

The Role of Disturbance, Topography, and Forest Structure in the Development of a Montane Forest Landscape
Keith S. Hadley
Bulletin of the Torrey Botanical Club
Vol. 121, No. 1 (Jan. - Mar., 1994), pp. 47-61

Abstract: 
Human set fires beginning in the mid 1800s and repeated insect outbreaks of western spruce budworm (Choristoneura occidentalis Free.) and Douglas-fir bark beetle (Dendroctonus pseudotsugae Hopk.) during the past 50 years have resulted in a dramatic change in the montane (<ca. 2900 m) forest landscape of the Colorado Front Range. Here, I examine the historical and spatial relationship between these disturbance agents and topography using stand structure and dendroecological data from 38 contiguous stands. These data suggest that aspect and relief are important factors determining the spatial and temporal patterns of disturbance, succession, and rates of stand development. The rate of postfire stand development and hence, subsequent stand susceptibility to insect outbreaks appears to be related to aspect. North-facing stands experience rapid postfire development and greater susceptibility to insect attack due to higher host tree densities, larger mean tree size, and a more uniform distribution of host trees over larger contiguous areas. Postfire stand recovery on south facing slopes appears to be slower and stand susceptibility to insect attack is less due to lower host densities, smaller mean tree size, and a less uniform distribution of host trees over smaller areas. Relief, independent of aspect, enhances the structural diversity of the forest landscape by promoting irregular burn patterns and intensities, thus creating a fire-induced mosaic of different aged stands. As these different aged stands continue to grow older, they reach a stage of development susceptible to insect outbreaks at different times. As a result, insect-induced changes in the structural characteristics of the current landscape emulate fire-induced landscape patterns that developed largely due to human activities beginning in the 1860s.

Culvert flow in small drainages in montane tropical forests: observations from the Luquillo Experimental Forest of Puerto Rico.

Scatena, F. N. 1990. Culvert flow in small drainages in montane tropical forests: observations from the Luquillo Experimental Forest of Puerto Rico. . Tropical Hydrology and Caribbean Water Resources. :237-246.

Abstract: 
This paper describe the hydraulics of unsubmerged flow for 5 culverts in the Luiquillo Esperimental Forest of Puerto Rico. A General equation based on empirical data is presented to estimate culvert discharge during unsubmerged conditions. Large culverts are needed in humid tropical montane areas than in humid temperatute watersheds and are usually appropriate only for drainage less than 1km2.
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