Prescribed Burn Effects on Natural Regeneration in Pine Flatwoods: Implications for Uneven-Aged Stand Conversion from a Florida Study

Uneven-aged silvicultural approaches are increasingly utilized as efficient management strategies for economic and ecological sustainability of forest resources, including in the southeastern United States where there is interest in converting intensively managed pine plantations to uneven-aged stands. However, success of stand conversion and perpetuation of an uneven-aged forest stand depends on obtaining adequate regeneration of the desired species and its ability to develop into merchantable size classes. In fire-maintained ecosystems, regeneration dynamics can be challenging for species such as slash pine that are not tolerant of fire in the seedling stage. In this study, we examined the survival of slash pine (Pinus elliottii Englm.) regeneration (seedlings and saplings) following prescribed burns in (1) a harvest-created gap (0.4 ha; 70 m diameter) and (2) a mature stand with abundant advanced regeneration at two mesic-hydric flatwoods sites in northwest Florida, USA. We characterized the prescribed burns at the two sites and quantified survival of regeneration of different size classes (<1 m, 1–2 m, 2–3 m, >3 m) at 10 months after the burn. Within the gap, the greatest survival of regeneration was observed at the center (12.5% survival) in comparison to the other positions in the gap (1.92% to 7.14% survival), with all seedlings <3m height killed by the burn. In the stand with advance regeneration, survival ranged between 0% and 50% at different positions, with all regeneration smaller than 2 m killed by fire. Overall, we observed 6.36% and 23.2% survival in the harvest-created gap and the stand with advance regeneration, respectively. Despite these low percent survival values, post-burn slash pine regeneration (seedlings/saplings) density equaled 725 and 4800 per hectare, respectively. Our modeling projections suggest that this level of post-burn regeneration density may be adequate for stand conversion and sustainable uneven-aged silvicultural management of slash pine. These results suggest that seedling size is the preeminent control on slash pine survival after prescribed burn. However, long-term monitoring of stand dynamics following future prescribed burns and cutting cycle harvests will help confirm if slash pine can be sustainably managed using uneven-aged silviculture.

Productivity and Cost of Integrated Harvesting of Wood Chips and Sawlogs in Stand Conversion Operations

This study evaluated the operational performance and cost of an integrated harvesting system that harvested sawlogs and biomass (i.e., energy wood chips) in stand conversion clearcut operations. Douglas-fir (Pseudotsuga menziesii) trees were processed into sawlogs while whole trees of tanoak (Lithocarpus densiflorus), and sub-merchantable materials (small-diameter trees, tops and limbs) were fed directly into a chipper to produce biomass for energy production. A standard time study method was used to determine productivity and costs. Over 26 working days, the integrated system produced 1,316 bone-dry metric tonnes (BDTs) of sawlogs, and 5,415.89 BDT of chips, with an average moisture content of 43.2%. Using the joint products allocation costing method, the costs of the integrated system were $29.87/BDT for biomass and $4.26/BDT for sawlogs. Chipping utilization was as low as 41%, directly affecting production and cost of chipping operation. Single-lane, dirt, spur roads were the most costly road type to transport whole trees to a centralized processing site: transportation costs for biomass and sawlogs were increased by $0.08/BDT and $0.02/BDT, respectively, for every 50 meter increase in traveling distance. Diesel fuel price could raise total system cost for each product by $0.78/BDT and $0.08/BDT for each $0.10/liter increase.

Stand conversion by means of natural succession in the Białowieża Primeval Forest

Przebudowa drzewostanów z wykorzystaniem naturalnych procesów sukcesyjnych w Puszczy Białowieskiej

Rapid capture of growing space by red maple

Red maple ( Acer rubrum L.) is becoming increasingly dominant in forest stands throughout the eastern United States. To investigate the reasons for the increase, we examined the development of red maple and oak ( Quercus spp.) seedlings and stump sprouts following the harvest of oak-dominated stands. Within 7 years after harvest, red maple seedlings were present in far greater numbers and captured more growing space than all oaks combined. Growing space occupied by red maple stump sprouts exceeded oak sprouts by a ratio of 3.5:1. Through stump sprouts alone, red maple fully recaptured the amount of growing space it had previously occupied in the overstory 7 years after harvest. Results from similar but older stands show that red maple dominance is sustained into the third decade of stand development. Red maple surpassed all oaks combined in rapid site capture through both seed-origin and sprout-origin regeneration. Red maple’s superior ability to regenerate by sprouts is particularly favored by timber harvesting following a history of management and disturbance regimes that permit the accumulation of suppressed small-diameter red maple stems. Among the events and processes that promote stand conversion, timber harvesting may be the major proximal cause of the widespread, increasing dominance of red maple.

An economic aspect of conversion of Scots pine (Pinus sylvestris L.) stands in the Polish Lowland

Pine stands at fertile sites need conversion into broadleaved or mixed forests. Yet, according to the age of stand, conversion may have different economic results. Therefore, in order to reduce costs of the process, the analysis on the basis of the potential income from wood sale has been done. The aim of the analysis has been to find an optimal date of conversion beginning. The date of conversion beginning has been fixed on the basis of the relation of the value of wood increment from the stands which need conversion to the value of average wood increment from stands conformable to the sites. By this means, three age intervals have been appointed.