Todd S. Fredericksen

Effect of disturbance intensity on regeneration mechanisms in a tropical dry forest

We examined the effect of disturbances of varying intensity on the dominant modes of regeneration among woody plants in tropical dry forest in lowland Bolivia. Seed survival and density, mortality, height, crown area, and basal diameters of seedlings and sprouts were compared among four treatments of varying disturbance intensity (high-intensity burn, low-intensity burn, plant removal, and harvesting gap) over a period of 18 months following treatments. High- and low-intensity burns reduced densities of viable seed by an average of 94 and 50%, respectively. Tree seedlings were more abundant than tree sprouts in all treatments. There were few differences in seedling density among treatments. Sprouts were most common in the plant removal and low-intensity burn treatments than in harvesting gap and high-intensity burn treatments. Seedling mortality was higher than sprout mortality during the first year following treatments. Sprouts were taller, had more stems per individual, larger crown areas, and larger basal diameters than seedlings. Origin of sprout differed among treatments. Eighteen months following treatments, 85% of individuals >2.5 m tall were sprouts. Most seedlings >2.5 m tall after 18 months had established in high-intensity burn treatments. Sprouting individuals dominated regeneration after all treatments, however, in high-intensity burn treatments, sprouts were relatively less dominant due to smaller sprouts and larger seedlings after high-intensity burns.

Post-fire tree regeneration in lowland Bolivia: implications for fire management

Abstract Tree regeneration was compared in burned and unburned portions of a tropical dry forest (1110xa0mmxa0ppt/year) and a tropical humid forest (1542xa0mmxa0ppt/year) in southeastern Bolivia. Both forests burned 5 years prior to our study, and both forests were also lightly selectively logged ( intensity m 3 /ha ) —the dry forest during the 1970 and 1980s and the humid forest just prior to the wildfire. The objective of this study was to compare abundance, size, and mode (seedling or resprout) of tree regeneration in burned and unburned areas of these forests, focusing on the most common canopy tree species and the commercial timber species at each site. Regeneration of 13 species of trees was quantified in the humid forest and 12 species in the dry forest. Tree regeneration 20xa0cm tall was more abundant in the dry forest ( x =1807 stems/ha ) than in the wet forest (x=490 stems/ha ) . In both forests, resprouts were generally larger but less abundant than seedlings. In the dry forest, regeneration of the following commercial tree species was significantly more abundant in the burned areas: Cedrela fissilis , Anadenanthera colubrina , Astronium urundueva , and Centrolobium microchaete . However, Acosmium cardenasii , a canopy tree species not marketed for timber in Bolivia, represented the majority of regeneration (63%) in the dry forest and was equally abundant in burned and unburned areas (∼1100xa0stems/ha). In the humid forest, only one timber species, Aspidosperma rigidum , was more abundant in burned than unburned areas (51 vs. 0xa0stems/ha, respectively). Another timber species that is rarely harvested in the region, Pseudolmedia laevis , was significantly less abundant in the burned than unburned area (22 vs. 173xa0stems/ha, respectively). The results of this study suggest that controlled burning could increase the abundance of timber tree regeneration at the dry forest site and to a lesser extent at the humid forest site. No data were collected to assess the likelihood that this increased density of regeneration will result in increased harvestable timber. However, local forest management institutions do not presently appear capable or motivated to conduct fire management—whether for enhancing timber regeneration or for limiting the damage caused by accidental wildfires.

Comparative regeneration ecology of three leguminous timber species in a Bolivian tropical dry forest

A comparative study of the regeneration ecology ofthree lesser-known leguminous timber species wasconducted in the seasonally dry forests of SantaCruz, Bolivia to determine species regenerationstrategies and make silvicultural recommendationsfor these species. The study included arepresentative from each subfamily of Leguminosae:Anadenanthera colubrina (Vell. Conc.) Benth.(Mimosaceae), Copaifera chodatiana Kunth.(Caesalpinaceae), and Centrolobium microchaeteC. Martius (Fabaceae). After production in themid-late dry season, seeds of all species sufferedhigh (>30%) rates of predation. For seedssurviving predation, Anadenanthera germinatedwithin three days after the first rains and a highgermination capacity (82%), but most seedlings diedfrom inadequate light or during subsequent periodsof drought. Copaifera germinated more slowlybut had high germination capacity (85%). Centrolobium had very low germination capacity(4%) and germinative energy. Most successfulregeneration of Centrolobium occurred viasprouting from damaged roots on or near loggingroads where it had a density of 261 root sprouts/ha.Anadenanthera regenerated best from seedin areas with soil disturbance or burning. Theregeneration of these species will likely increaseunder more intensive logging and/or post-harvestcompetition control treatments in logging gaps. Themore shade-tolerant Copaifera is most suitedto the current regime of light selective logging,but all three species are likely to be responsive topost-harvest competition control treatments. Impacts of controlled and natural fire were mixed,but generally seedling regeneration and growth wereeither not significantly affected or were increasedby fire.

Timber tree regeneration along abandoned logging roads in a tropical Bolivian forest

Sustainable management of selectively logged tropical forests requires that felled trees are replaced through increased recruitment and growth. This study compares road track and roadside regeneration with regeneration in unlogged and selectively logged humid tropical forest in north-eastern Bolivia. Some species benefited from increased light intensities on abandoned logging roads. Others benefited from low densities of competing vegetation on roads with compacted soils. This was the case for the small-seeded species Ficus boliviana C.C. Berg and Terminalia oblonga (Ruiz & Pav.) Steud. Some species, e.g. Hura crepitans L., displayed patchy regeneration coinciding with the presence of adult trees. Our results suggest that current management practices could be improved by intensifying logging in some areas to improve regeneration of light demanding species. Sufficient seed input in logged areas should be ensured by interspersing large patches of unlogged forest with logged areas. This may also assist regeneration of species that perform poorly in disturbed areas.

Invasion of Non-Commercial Tree Species After Selection Logging in a Bolivian Tropical Forest

Abstract Single-tree selection logging will likely result in a 4.3% loss in the relative abundance and a 4.1% loss in basal area of trees of commercial species in one cutting cycle due to their removal by harvesting combined with their potential recolonization of only 31% of logging gaps in a Bolivian tropical dry forest. Densities of the most valuable species, Amburana cearensis and Cedrela fissilis, were particularly reduced by logging. To sustain the current harvesting rate, uses need to be developed for more non-commercial species and/or silvicul-tural treatments employed that increase regeneration of commercial species and remove non-commercial species using timber stand improvement techniques.

Thermal Regulation and Habitat use of the Eastern Box Turtle in Southwestern Virginia

Abstract n While Terrapene Carolina Carolina (Eastern Box Turtle) are found over a wide geographic range, they appear to select microhabitats based on the need for thermoregulation, minimization of water loss, and reproduction. Habitat selection and the activity patterns of Eastern Box Turtles in southwestern Virginia were studied in relation to short-term weather conditions and seasonal variation. Turtles were located using telemetry 36% of the time in the interior of mature forest habitats, 23% in edge habitats, 18% in fields, 7% in a 22-year-old Pinus strobus (Eastern White Pine) plantation, 7% in forest canopy gaps, 5% in a 4-year-old clearcut, and 4% in streams. We observed a seasonal shift in habitat use, with more turtles using mature forest habitat compared to other habitat types in all months, except for May when 47% of all turtles were located in edge habitat. Also, Eastern Box Turtles often selected canopy gaps within forests during the fall, and females moved from forests to recent clearcuts during the nesting season, which accounted for a larger home-range size. As expected, turtle activity was lower during hot, dry periods in midsummer and decreased gradually during the autumn with decreasing temperature. Rainfall increased turtle activity, especially when following prolonged dry periods.

Effect of human disturbance on the structure and regeneration of forests in the Nevado de Toluca National Park, Mexico

Sample plots were established in the principal forest types in the the Nevado de Toluca National Park, Mexico including those dominated by Pinus hartwegii, Abies religiosa, Quercus laurina and Alnus jorullensis. The vertical structure was defined by three strata in the coniferous forests and two strata in the broadleaved forests. Timber harvesting in Abies religiosa and Quercus laurina forests and fires generated by humans in Pinus hartwegii forests impeded the recruitment of saplings. Mature trees were also heavily impacted by logging in Pinus hartwegii forests. On the contrary, Alnus jorullensis forests were increasing due to the disturbance of Pinus and Quercus forests, as well abandoned crop lands within the park. A combination of logging, uncontrolled fire, and grazing appears to be compromising the recruitment of important tree species in this national park. These factors, together with human settlements, have also increased the proportion of early successional species. Changes in forest structure from human disturbance indicate a need to control these activities if conservation goals are not to be compromised.

Silvicultural intensification for tropical forest conservation: a response to Sist and Brown

We welcome the comments by Sist and Brown (henceforth S & B) about our suggestion that in some tropical forests, silvicultural interventions need to be intensified to promote regeneration of some commercially valuable species and to otherwise sustain timber yields. Although there is nothing particularly new about this suggestion, it is often lost in campaigns to minimize the deleterious environmental impacts of logging. We also applaud S & B’s efforts to promote reduced-impact logging (RIL) and agree that for forests well stocked with advanced regeneration of commercial species, maintaining pre-intervention forest structure by using RIL techniques represents a major step towards the goal of sustainable forest management. Given how difficult it is to improve logging practices (e.g., Putz et al. 2000; Blate et al. 2001), even when application of RIL techniques would be to the loggers’ short-term financial advantage (e.g., Holmes et al. 2002), S & B’s emphasis on logging to the exclusion of other silvicultural interventions seems justified. Also, if we had actually made a blanket endorsement of the creation of extremely large felling gaps, which was apparently S & B’s interpretation, we would share their concern about proliferation of vines and other weeds. Instead, we argued that there are conditions under which any of a number of silvicultural treatments, such as gap enlargement, vine cutting, liberation of future crop trees, and soil scarification, can be justified if they promote the regeneration and growth of commercial species. Ultimately, maintaining the value of forests for timber production may be the best incentive for keeping forests from being converted to other land uses.

Regeneration patterns of Eastern white pine (Pinus strobus L.) in hardwood-dominated forests in Virginia, USA.

Eastern white pine (Pinus strobus L.) is a moderately shade-tolerant species that co-occurs with hardwood tree species in many forests of the eastern United States, as well as in pure stands. The species is valued for its timber, as well as for wildlife and recreation. Regeneration of this species is somewhat unpredictable and often occurs in patches of similarly-aged cohorts. We described the regeneration patterns of this species and examined their relation to environmental variables within hardwood forests of southwestern Virginia, USA. An average of 5.3 white pine patches per ha were observed in this study. The majority of patches consisted of saplings (85%), with 9% of patches in pole size classes, and 6% in seedling size classes. The average density of patches was 43.5 stems with an average age of 20xa0years. The size of patches averaged 80.6xa0m2. The total density of seedlings and the number of regeneration patches of all sizes of regeneration (seedlings, saplings, and poles) in plots was related to the surrounding density of large white pine trees (potential seed trees). The density of seedlings or patches was not significantly related to current vegetation cover or soil surface cover variables, but more than half of regeneration patches were located in or adjacent to old canopy gaps, most of which were old logging gaps. While seedling regeneration may occur within the understory of these forests near seed trees, advancement to the sapling and pole stage appears to be associated with canopy gap formation.

Erratum to: DOI duplications

Eight articles in Journal of Forestry Research were published online but then became inaccessible when a technical error led to eight other articles being published with the same DOIs. They were then republished under new DOIs, as listed below: Article: Anthropogenic disturbances and status of forest and wildlife in the dry deciduous forests of Chhattisgarh state in India Original Article: Characterization of 14 anonymous nuclear loci in Pinus thunbergii and their cross-species transferability Original The publisher sincerely apologizes to all concerned and regrets the inconvenience caused.