Treesearch

Traditional agroforest systems exist throughout Micronesia. The system found on one Micronesian group of islands, Yap, is described and evaluated in ecological terms. Implications for future development of agriculture in Micronesia are discussed and some specific recommendations are given.

Mixed cropping (including agroforestry) often gives yield advan-tages as opposed to monocropping. Many criteria have been used to assess yield advantage in crop mixtures. Some of these are presented. In addition, the relative merits of replacement, additive and bivariate factorial designs are discussed. The concepts of analysis of mixed cropping are applied to an example of an alley cropping (a type of agroforestry) experiment, and a basic agroforestry research guide is described.

Traditional land use classification on Yap Island, especially in regards to agroforestry, is described. Today there is a need to classify land on Yap to protect culturally significant areas and to make the best possible use of the land to support a rapidly growing population. Any new uses of land should be evaluated to assure that actions in one area, even private property, do not damage the property of others.

Recent interest in indigenous agroforestry has led to a need for documentation of these systems. However, previous work is very limited, and few methodologies are well-known or widely accepted. This paper outlines various methodologies (including sampling methods, data to be collected, and considerations in analysis) for documenting structure and productivity of indigenous agroforestry systems, using references to previous documentation studies carried out in other parts of the world.

Introduction of new crops in agroforestry is often suggested as a way to improve productivity. This paper provides general guidelines in selecting companion plant combinations and general considerations in evaluating, testing, naming, maintaining genetic purity and distributing crop varieties to farmers.

The forest is an integral part of the island ecosystem, and any indiscriminate destruction is bound to cause a shift in the climatic conditions, increased soil erosion, and other effects. The conservation of existing forestry is of great importance. Future patterns of agricultural development in the Pacific Islands should aim to integrate with the forest cover rather than eliminate it. Climatically, Pohnpei is regarded as one of the best sites in the world for the cultivation of a range of high value spice crops. One spice crop that will thrive well in the existing forests above 1500 m is...

Pacific Islands agroforestry has evolved into sustainable, diverse and productive a land use systems in many areas. We marvel at these systems, and the scientific world is trying to catch up with the traditional knowledge. At the same time, Pacific Islands farmers are abandoning their agroforestry systems in great numbers. It is mainly intensified agriculture for cash crop production that follows. Soil erosion and soil fertility deficiencies are close companions of this intensification. Why do land use systems that have been operative for centuries disappear so easily? Can "modern"...

Upland forests of Micronesia and American Samoa can provide many social, ecological, and esthetic benefits for island inhabitants. Substantial upland areas (the majority of acreage on some islands) are now occupied by secondary and grassland/savanna vegetation; such areas represent opportunities for restoration, with both native forest cover and plantations of introduced species. This review briefly describes characteristics of the islands and the nature of existing and potential upland forests, including the most common upland tree species. Principal information needs and research...

Biological control traditionally depends upon importing the natural enemies of introduced weeds. Since vegetation management in forestry has primarily been aimed at protecting economic species of trees from competition from other native plants, biological control has been of little use in forestry. An alternative approach to controlling unwanted native plants, supplementing their existing complex of natural enemies with introduced insects found attacking closely related plants, is being used on rangeland, but is not recommended for forestry. New agents will not remain restricted to the...

Little is known about the concentrations, deposition rates, and effects of nitrogenous and sulfurous compounds in photochemical smog in the San Bernardino National Forest (SBNF) in southern Calfirnia. Dry deposition of NO3- and NH4+ to foliage of ponderosa pine (Pinus ponderosa Laws.) and Jeffrey pine (Pinus jeffreyi Grev. & Bay) was correlated (R = 0·83-0·88) with historical average hourly 03 concentrations at 10 sites across an O3 gradient in the SBNF. Mean deposition fluxes of NO3- to ponderosa and Jeffrey pine branches were 0·82 nmol m-2 s-1 at Camp Paivika (CP), a high-pollution site,...