Joe P. Colletti

Agroforestry opportunities for the United States of America

Agriculture in the United States makes intensive use of large portions, of the nations arable landscape. This landscape is dominated by large fields of annual crops with few perennial buffering communities within them. Agroforestry systems such as riparian buffers, alleycropping, windbreaks, tree/pasture systems, and forest farming provide buffering opportunities within these landscapes. Riparian buffers and alleycropping systems provide two unique opportunities toward sustainable production by reducing nonpoint source pollution while increasing ecological diversity. The major impediment to agroforestry in the United States is a lack of identity. Agroforestry as a practice is not officially recognized by federal and most state agencies and thus does not qualify for cost-share support or funding for research and establishment of demonstrations. A recent white paper, prepared by representatives from government agencies, academic institutions, and nongovernment organizations, identified eight major actions that could provide the support, for making agroforestry an acceptable alternative to nonsustainable agriculture. Ames, Iowa. Project No. 3209.

Optimal forest stock and harvest with valuing non-timber benefits: a case of US coniferous forests

Abstract How much to cut and to remain, as well as when to cut is an important decision-making issue in forest management. Unlike forest age, forest stock and harvest levels are applicable to both plantations and natural forests. This paper investigates the optimal forest stock and harvest with the consideration of both timber and non-timber benefits. The impacts of the discount rate, silvicultural cost, marginal timber benefit, and marginal non-timber benefit on the optimal forest stock and harvest are also examined. The results indicate that forest stock should be thickened when non-timber benefits are valued in addition to timber. The optimal steady state stock increases with a decrease in the discount rate, or an increase in marginal non-timber benefit. However, the impacts of the discount rate, marginal timber benefit, and marginal non-timber benefit on the optimal steady state harvest are ambiguous. In addition, a decrease in the discount rate has the same effect on the optimal steady state stock and harvest as an increase in the ratio of marginal non-timber benefit to marginal timber benefit. These theoretical results are illustrated through an empirical example of the US coniferous forests.

Willingness of Iowa agricultural landowners to allow fee hunting associated with in-field shelterbelts

In 2004, four focus groups consisting of agricultural landowners were organized in Northcentral Iowa to assess opportunities for hunting along in-field shelterbelts and on adjacent lands. A majority of respondents (95%) allowed/practiced some hunting on their lands. About 55% of respondents indicated that the potential existed for developing a fee hunting market associated with in-field shelterbelts. Intangible features of hunting, such as recreation/enjoyment and better land stewardship, were ranked higher than tangible ones—additional income and provision of economic opportunities for local communities. Respondents were highly concerned with negative consequences of hunting—trespassing and hunter misconduct. On average, agricultural landowners were willing to accept (WTA) US

Estimates of additional Maize (Zea mays) yields required to offset costs of tree-windbreaks in Midwestern USA

30 per visit per party of four hunters to allow hunting of ring-necked pheasants (Phasianus colchicus) on their land. About 33% would grant access to hunters free of charge. Those who lived in urban areas would require five times the monetary compensation (US

Corn stover as a biofuel feedstock in Iowa's bio-economy: an Iowa farmer survey.

50) as those who lived in rural areas (US

Mitigating swine odor with strategically designed shelterbelt systems: a review

10).

Valuation of open space and conservation features in residential subdivisions.

Field windbreaks can increase crop yield within a protected zone. However, they also take land out of crop production and compete with adjacent crops. Although the beneficial aspects are generally recognized, the question arises whether the windbreak will increase crop revenue enough to offset costs over time. Achieving additional yields to offset windbreak costs might be a sufficient incentive for a producer to plant a windbreak. Additional maize (Zea mays) yields necessary to break even with costs are calculated for four typical Midwestern USA field windbreaks: poplar (Populus spp.), mixed tree/shrubs (Populus spp., Acer saccharinum L./Physocarpus spp., Viburnum spp., Cornus spp.), and two and four-row spruce (Picea spp.) windbreaks. Five lifespans, two management and two cost scenarios, and three protected zone widths to account for changing sheltering effects are evaluated. Greatest additional yields are for a 4-row spruce windbreak with intensive management at high cost and a 10-year lifespan: 15.38 Mg ha–1 yr–1 within 6H, 7.69 Mg ha–1 yr–1 within 12H and 6.15 Mg ha–1 yr–1 within 15H. If a 50-year lifespan is implemented, the additional yields are about 11% of those in 10-year lifespan. Smallest additional yields are for a mixed tree/shrubs windbreak with extensive management at low cost and a 50-year lifespan: 0.56 Mg ha–1 yr–1, 0.28 Mg ha–1 yr–1 and 0.22 Mg ha–1 yr–1, respectively. The mixed windbreak is likely to have actual maize yield increases comparable to the added maize yields required to break even as long as the lifespan is 30 years or longer with a minimum protected zone of 12H.