Todd W. Bowersox

Growth response of northern red-oak and yellow- poplar seedlings to light, soil moisture and nutrients in relation to ecological strategy

Abstract Northern red oak ( Quercus rubra L.) and yellow-poplar ( Liriodendron tulipifera L.) were grown from seed in containers for two seasons in six environments consisting of three levels of edaphic richness (high-moisture/high-fertility, high-moisture/low-fertility, low-moisture/high-fertility) and two light intensities (100%, 20% full sun). Seedling height, dry weights of leaves, stems, and roots, and projected leaf and root surface areas were measured at the end of the second growing season. Low levels of light, moisture, and fertility significantly reduced growth of both species, and effects of low moisture and low fertility were greater in full sun than in shade. Total dry-weight of yellow poplar was 36% greater than that of red oak under combined high levels of light, moisture, and nutrients, while total dry-weight of oak was 38–126% greater than that of poplar where at least one resource was at a suboptimal level. Reductions in growth for yellow-poplar due to low levels of all resources were greater than those for red oak, indicating greater stress tolerance for oak. Yellow-poplar had significantly greater shoot: root ratio and greater partitioning of leaf and root mass to absorbing surfaces compared to red oak. The relative tolerance of red oak to low resource levels and morphology suggests adaption to moderately unproductive environments (stress-tolerant strategy), while the characteristics of yellow-poplar (opportunistic capture of plentiful resources, maintenance of large absorbing surfaces) suggests adaptation to more productive environments (competitive strategy). The growth strategy of red oak is discussed in relation to ecological requirements for regeneration.

Northern red oak planting stock: 6-year results

A northern red oak plantation was established in 1988 in a recently clearcut mixed oak stand to evaluate outplanting performance relative to type of planting stock (1--0, 2--0, 1--1, 2--1, 2-year-old containerized, and direct-seeded) and other cultural factors (undercutting in the nursery, raising stock in an extended growing season in Alabama vs a local Pennsylvania nursery, top-clipping at planting time, and tree shelters). Six years after outplanting, seedlings grown from 2-year-old containerized stock were tallest (averaging 3.3 m) and had excellent survival. Among other treatments, 2--0 bareroot stock, especially if undercut in the nursery and top-clipped at planting, performed best and averaged 3.0 m height and 100% survival. Remaining treatments, especially 1--0, were smaller and had reduced survival. Seedlings from direct-seeding were as tall as most 1--0 treatments. Undercutting, top-clipping, nursery transplanting, raising stock in different nurseries, and tree shelters minimally affected the height or survival of seedlings. Seedlings above average in height 3 years after outplanting when fencing was removed and herbiciding ceased, were most likely to survive after 6 years.

Economic evaluations of multiple rotation sric biomass plantations

Abstract A series of short-rotation intensive culture (SRIC) Populus plantations involving four management strategies (control, fertilization, irrigation, and fertilization-irrigation) were evaluated in tandem with alternate harvesting and storage strategies to determine the least cost method for supplying biomass to an ethanol conversion facility. The plantations were based on Populus hydrid NE-388, a tree spacing of 0.6 m × 0.8 m, and a rotation length of four years. First rotation yields from the various strategies ranged from 33 to 42 oven-dry metric tonne per hectare (Mg(OD) ha−1). An average yield increase of 12% was realized from the second rotation coppice plantations. The control strategy had the lowest production costs for the two rotations, averaging 532 Mg−1 (OD). Harvesting and storage requirements nearly doubled the final costs, with the least cost system having an average total cost of

Short rotation woody biomass plantations: Technical requirements and costs for establishment

66 Mg−1 (OD). Over 50% of the total cost originated from equipment and material inputs, with labor costs representing nearly 30% of the total and land the final 20%.

Production costs for first rotation biomass plantations

Abstract The establishment of short rotation, intensive culture, (SRIC) woody biomass plantations using hybrid poplar was cost analyzed on a financial and energy input basis. Establishment operations were at a commercial scale and met the power requirements of each task in a cost-efficient manner. Total establishment costs amounted to

Financial selection of rotation age for SRIC plantations

1249 ha−1 and, on an energy cost basis, 16205 MJ ha−1. The planting operation was the largest expense, involving 73% of the total financial and energy costs in establishment. The second largest expense was herbicide spraying, costing approximately 22% on a financial and energy basis. In turn, establishment represented 36% of the total production costs in the 4-year rotation of non-fertilized plantations.

Coppicing success of young Eucalyptus saligna in Hawaii

Abstract A series of short rotation Populus plantations involving alternate management strategies were evaluated in terms of the financial and energy costs required in the production process. The plantations used hybrid poplar NE-388 ( Populus maximowiczii × trichocarpa ), a tree spacing of 0·6 m × 0·8 m and a rotation length of 4 years. Four production strategies (control, irrigation, fertilization, and fertilization-irrigation) were employed on sites representing favorable and unfavorable growing conditions. The production costs were based on a proposed commercial design involving a plantation unit of 924 hectares, with 4 such units providing a sustainable supply of biomass. The control strategy on the better site was least expensive, with base stumpage costs of

Cost parameters affecting multiple rotation SRIC biomass systems

28·71 Mg −1 ovendry (od). The addition of fertilizer on the better site increased the financial costs for the product by 24·0% and the energy costs by 5·4%. Irrigation on the better site more than tripled the financial costs for the stumpage product and caused a 20·6% increase in its energy costs.

Financial and energy costs of supplying woody biomass to conversion sites

Abstract Short rotation intensive culture (SRIC) plantations, established in central Pennsylvania, were analyzed to determine their economic optimum rotation age. The general management design for the plantations used fertilized and non-fertilized strategies, a tree spacing of 0·48 m 2 and a rotation length of 4 years. A stand-level financial model analyzed the unit cost of production for alternate rotation lengths based upon the plantations investment and operating costs and resulting biomass yields. Analysis of the first two rotations indicated that the minimum unit cost for fertilized and non-fertilized strategies was in the fourth year of the first rotation and the third year of the second rotation. Growth curves for the rotations also showed a maximum volume production at the same points in the rotations. Selection of a 3-year rather than 4-year harvest during the second rotation would reduce unit costs by 14% in the non-fertilized strategy and by 15% in the fertilized strategy.

Developing financial and energy accounting models for woody biomass systems

Abstract Coppicing characteristics of felled 3-year-old E. saligna trees growing in Hawaii were evaluated for four DBH classes and two stump-height segments. About 40% of all the stumps had at least one living shoot > 2 cm at the end of the 20-week study period. Tree size before felling had no effect on number of dormant buds available to develop into shoots, sprouting success or length of the longest sprout per stump, but all of these variables were affected by stump-height segment. Standardized 20-cm stump segments above the lowest branch scars (about 34–60 cm above ground) had about double the number of dormant buds, sprouting success and length of the longest shoot per stump than stump segments below the lowest branch scars. Ambrosia-beetle attacks on the stumps were coincidental with coppice development (2–8 weeks after felling), and were less severe on the stumps from the smaller trees and on the upper stump segments. Reasons for the low coppicing success of E. saligna in Hawaii are unknown. The opportunity for coppice (frequency of dormant buds) and the disturbance of coppicing by ambrosia beetles need to be more fully understood before coppicing can be a dependable method of regenerating this species in short-rotation intensive culture plantations in Hawaii.