Ecological research at the Blacks Mountain Experimental Forest in northeastern California

Abstract

At Blacks Mountain Experimental Forest in northeastern California, an interdisciplinary team of scientists developed and implemented a research project to study how forest structural complexity affects the health and vigor of interior ponderosa pine (Pinus ponderosa Dougl. ex Laws.) ecosystems, the ecosystem's resilience to natural and human-caused disturbances, and how such ecosystems can be managed for sustained resource values. A randomized, split-plot, factorial design has been developed to test the influences of structural diversity, cattle grazing, and prescribed fire on twelve 250-acre study units. A permanently monumented data reference system on a 100-meter (328-ft) grid will facilitate spatial and temporal analysis as well as integration of information at various scales. Intensive preliminary sampling has established baseline data on small mammal and avian diversity and behavior, forest vegetation structures and floristic diversity, historical fire patterns, bark beetle dynamics, soil properties and processes, and genetic structure of pines and understory species.

Resiliency of an Interior Ponderosa Pine Forest to Bark Beetle Infestations Following Fuel-Reduction and Forest-Restoration Treatments

“…Following harvesting, half of each plot was treated with prescribed fire in fall (B) ( Table 1). For a comprehensive description of treatments and a depiction of their placement on the landscape, see Oliver [12]. Earlier, we described climatic conditions, fuel moistures, and other parameters associated with prescribed burns [36].…”

“…Prior to treatment, stands within the study area were dominated by two age cohorts consisting of 300-500 year-old Pinus (P. ponderosa and P. jeffreyi) and incense cedar, Calocedrus decurrens (Torr.) Flori, with a dense understory and mid-story of 50-100 year-old Pinus, A. concolor, and C. decurrens [12]. There were 32.4 ± 1.5 (mean ± SEM) m 2 /ha of basal area and 871 ± 58 trees/ha [43].…”

“…& Balf. Frequent thinning of small-diameter (<19 cm diameter at breast height (dbh), 1.37 m) and fire-intolerant trees by low-intensity surface fires, and competitive exclusion of tree seedlings by understory grasses are believed to have maintained such conditions [12]. Today, many of these forests are denser, have more small trees and fewer large trees, and are dominated by more shade-tolerant and fire-intolerant tree species, such as white fir, Abies concolor (Gord.…”

“…Our work is part of a long-term ecological research project (Blacks Mountain Ecological Research Project) managed by the Pacific Southwest Research Station (USDA Forest Service), and conducted at large spatial scales that represent reasonable management scenarios in interior P. ponderosa. The primary objectives of the Blacks Mountain Ecological Research Project are to enhance understanding of the effects of forest structural complexity on the health and vigor of interior P. ponderosa forests; to quantify resilience to natural and human-caused disturbances; and to determine how these forests can be managed for sustained resource values [12]. In other work, we described the effects of structural diversity and the application of prescribed fire on levels and causes of tree mortality two ( [36], sample period 1) and five years ( [37], sample period 2) following prescribed burns.…”

Historical growth plots in the Pacific Southwest

“…After the last measurement in 1998-99, the study was terminated and the stands incorporated into a new study designed to test the ecological effects of contrasting stand structures, grazing, and prescribed fire on these interior pine forests (Oliver 2000). • Location-Within the Blacks Mountain Experimental Forest…”