Treesearch

At two different locations in northeast California, an interdisciplinary team of scientists is initiating long-term studies to quantify the effects of forest manipulations intended to accelerate andlor enhance late-successional structure of eastside pine forest ecosystems. One study, at Blacks Mountain Experimental Forest, uses a split-plot, factorial, randomized block design. Twelve 100-ha. split plots provide for three replications of two levels of each of three treatments: (1) forest structural diversity--high (emphasizing latesuccessional attributes) versus low; (2) fire-reintroduction...

On a high quality site in northern California, frequency, density, foliar cover, and height were measured on every plant species present in an 8-acre clear-cut opening each year from 1976 through 1980. Plant species numbered 71, although no more than 62 were present during a given year. Categories of vegetation with the most plants per acre initially were shrubs, annuals and biennials, and ferns; at the end of the study the categories were annuals and biennials, graminoids, and shrubs. At the beginning of the study, bracken fern provided the highest amount of foliar cover, whereas 5 years...

Purpose of this presentation is to put channel monitoring in context of channel processes and dispel the myth of the learned sage walking up the stream channel observing changes in the channel and extrapolating how these changes came about without looking at the rest of the watershed. The message I want to convey is it is not only O.K.to peek at the rest of the watershed, but it is necessary to understand why change has occurred. Many of the other speakers over the next two days will probably reiterate this same point, again and again.

Planted forests have more than a millennium of history and represent the world's best hope for meeting global wood requirements in the twenty-first century. Advances in genetic improvement, nursery practices, stand establishment, and tending, harvesting, and manufacturing have boosted plantation yields to a higher level than at any point in history. Despite this, forest managers face a mounting challenge to demonstrate that plantation productivity is sustainable. Tackling this challenge requires a sound understanding of the principles of forest productivity, how they apply to a developing...

A study established in 1981 to monitor and study the growth response of 18 pre-commercially thinned plots in the coast redwood forest type on the Jackson Demonstration State Forest (JDSF) was re-measured recently. A report documenting the results of the last 12 years of growth response (1987-1998) is being developed currently by the principal researcher Jim Lindquist. Current publication plans are to produce a California Forest Note documenting the results. A brief background and some preliminary results are presented here.

In California, repairing sidewalk damage associated with tree roots exceeds $62 million annually. Efforts to reduce sidewalk damage have provided street tree managers with a variety of root barrier products. In this study, 3 types of root barriers were installed and evaluated to determine whether 1) internal vertical ribs prevented circling roots and 2) root development would be significantly reduced in the top 30 cm (12 in.) of soil. The 3 barriers tested included 1) a modified production container, partially left in place when planted (extension casing), 2) a commercial product with...

This study answers the question: Do the accrued benefits from Modesto’s urban forest justify an annual municipal budget that exceeds $2 million? Results indicate that the benefits residents obtain from Modesto’s 91,179 public trees exceeded management costs by a factor of nearly 2. In fiscal year 1997–1998, Modesto spent $2.6 million for urban forestry ($14.36/resident, $28.77/tree), and 74% of this amount was for mature tree care. Total annual benefits from Modesto’s urban forest were $4.95 million ($27.12/ resident, $54.33/tree). Net benefits for FY 1997– 1998 were $2,329,900 ($12.76/resi...

A pilot study was performed to measure the difference in parking lot microclimate resulting from the presence or absence of shade tree cover. Microclimate data from contrasting shade regimes were then used as input to a motor-vehicle emissions model. Model results were used to estimate the potential for regional increases in parking lot tree cover to reduce motor-vehicle hydrocarbon and nitrogen oxide (NOx) emissions.

The two native California oaks in the forest zone of California are California black oak (Quercus kelloggii Newb.) and tanoak (Lithocarpus densiflorus [Hook. and Arn.] Rehd.). Both are ancient species with many adaptations to withstand California's Mediterranean climate, but some weaknesses as well. Both sprout vigorously from the root crown and both produce copious amounts of acorns. Sprouting has been the primary reproduction mode of approximately 90 percent of trees in existing stands. Research on oak regeneration and seedling physiology has been limited and sporadic. No major research...

The preceding chapters of this book have provided infomation on the ecological characteristics of the San Bernardino Mountains, as well as the effects of ozone and other air pollutants on vegetation and soil in the San Bernardinos, and additional interactions with air pollution and forest health. This chapter focuses on the human aspects of air quality in the San Bernardino Mountains because of the desired connection between available scientific information, wider understanding and acceptance of that information, and movement toward policy and behavioral changes necessary to act on...