Dense Regrowth Research Articles

Comparative Efficacy of Injection Triamcinolone Acetonide given Intralesionally and through Microneedling in Alopecia areata.

Alopecia areata (AA) manifests as patchy hair loss and intralesional corticosteroid (ILCS) is usual therapeutic choice in limited disease. Microneedling is used for uniform delivery of topical agent to relatively larger areas may prove to be more efficacious than traditional ILCS. The present study prospectively compared microneedling to traditional intralesional delivery of triamcinolone acetonide (TA). Prospective randomized comparative study in 60 patients of AA restricted to scalp not requiring systemic treatment randomly divided into two equal groups. Group 1 patients underwent microneedling with local application of injectable TA and Group 2 patients were given injectable TA intradermally for a total of three sessions at 3 weeks interval. A mean regrowth of 66.36% in Group 1 and 69.75% in Group 2 at week 9 was seen which was comparative with no significant statistical difference between the two groups (P = 0.664). Thirteen patients achieved 100% regrowth at week 9 in Group 1 and 16 patients achieved 50%-99% regrowth in Group 2. ILCSs have been cornerstone in the treatment of limited AA, but depth of injecting drug cannot be controlled, microneedling whereas is an effective drug delivery system and also causes release of growth factors. In this study, injectable TA used intralesionally and topically with microneedling had nearly similar efficacy in causing regrowth of hair with microneedling resulting in a more uniform but less dense regrowth of hair with lesser adverse effects.

Self-thinning forest understoreys reduce wildfire risk, even in a warming climate

As climatic changes continue to drive increases in the frequency and severity of forest fires, it is critical to understand all of the factors influencing the risk of forest fire. Using a spatial dataset of areas burnt over a 65 year period in a 528 343 ha study area, we examined three possible drivers of flammability dynamics. These were: that forests became more flammable as fine biomass (fuel) returned following disturbance (H1), that disturbance increased flammability by initiating dense understorey growth that later self-thinned (H2), and that climatic effects were more important than either of these internal dynamics (H3). We found that forests were unlikely to burn for a short ‘young’ period (5–7 years) following fire, very likely to burn as the regrowing understorey became taller and denser (regrowth period), then after a total post-disturbance period of 43–56 years (young + regrowth periods), fire became unlikely and continued to decrease in likelihood (mature period). This trend did not change as the climate warmed, although increases in synoptic variability (mean changes in synoptic systems per season) had a pronounced effect on wildfire likelihood overall. Young forest and regrowth forest became increasingly likely to burn in years of greater synoptic variability and the time taken for forests to mature increased, but in years with the most severe synoptic variability, mature forests were the least likely to burn. Our findings offer an explanation for fire behaviour in numerous long-term studies in diverse forest types globally and indicate that, even in the face of a warming climate, ‘ecologically-cooperative’ approaches may be employed that reinforce rather than disrupt natural ecological controls on forest fire. These range from traditional indigenous fire knowledge, to modern targeting of suppression resources to capitalise on the benefits of self-thinning, and minimise the extent of dense regrowth in the landscape.

Does Thinning Homogenous and Dense Regrowth Benefit Bats? Radio-Tracking, Ultrasonic Detection and Trapping

Renewal ecology promotes the creation and enhancement of landscapes that support biodiversity and ecosystem services for humans. Silvicultural thinning of forest regrowth to reduce tree competition represents a form of active management that may also benefit biodiversity, especially where secondary regrowth dominates. However, ecological responses to thinning can be complex, particularly for insectivorous bats whose ecomorphology is often related to vegetation structure. Furthermore, thinning may affect multiple aspects of bat ecology (i.e., roosting and foraging). We assessed this in dense white cypress regrowth in the Pilliga forests of New South Wales, Australia, where recent experimental thinning created thinned stands (4 × 12 ha) surrounded by unthinned regrowth. We contrasted flight activity and roost selection of three narrow-space species with differing conservation statuses (Nyctophilus corbeni, N. gouldi and N. geoffroyi), plus one edge-space species (Vespadelus vulturnus). Radio-tracking over two maternity seasons revealed a preference by all species for roosting in dead trees that were slightly larger than the mean for available dead trees in the vicinity. Although all tagged bats were caught in thinned patches, only 6% of roosts were located there. In contrast, ultrasonic detectors recorded significantly greater activity for V. vulturnus (p = 0.05) in thinned than unthinned patches and no treatment difference for Nyctophilus spp. Systematic trapping using acoustic lures found a higher trap rate for N. gouldi in unthinned than thinned treatments, but no treatment effect for N. corbeni, N. geoffroyi and V. vulturnus. Our results reveal differential use of forest treatments by multiple species, emphasising the value of heterogeneous landscapes supporting thinned and unthinned patches of dense regrowth.

Bat communities respond positively to large‐scale thinning of forest regrowth

Summary Over half of the world's forests are secondary regrowth and support considerable biodiversity. Thinning of these forests is a widespread management practice that can affect forest species, including echolocating bats and their prey. We compared total activity of 11 bat taxa, foraging activity of six bat guilds and biomass of 11 insect orders across four forest thinning categories in managed remnant eucalypt forests in south‐eastern Australia: unthinned regrowth, forest thinned recently (0–4 years) and in the medium term (5–10 years) and reference (mature open forest). Thinning had been carried out at large (˜350 ha) spatial scales. Total bat activity was 60% less and foraging activity was 80% less in unthinned regrowth, compared to reference sites, but activity levels were similar among thinned and reference sites. Insect biomass was greatest in unthinned sites, and while bat activity was related to prey biomass, this relationship was weak in unthinned sites. Together, this suggests that forest structure was more important than prey availability or time since thinning in influencing bat activity patterns. Synthesizing our findings with the broader literature on bats and thinning, we found support for a clutter threshold of 1100 stems ha−1, above which bat activity was markedly lower, across two continents (the USA and Australia) and four broad vegetation types (eucalypt, conifer, deciduous and mixed forests). While elsewhere bats with adaptive traits for open habitats generally respond positively to thinning, in our study, species with traits consistent with clutter tolerance (high call frequency and low wing aspect ratio) had lowest activity levels (up to 22 times) in unthinned regrowth compared to all other forest types. Synthesis and applications. Widespread dense regrowth forest can restrict movement and foraging of bats, even those adapted to clutter. We recommend thinning dense regrowth or plantations to below 1100 stems ha−1 when targeting bat foraging habitat, but effects of thinning on roost habitat and other forest biota require further investigation.

The Speargrass (Imperata cylindrica (L) Beauv.) menace in Ghana: Incidence, farmer perceptions and control practices in the forest and forest-Savanna transition Agro-ecological Zones of Ghana

Surveys to determine farmers’ practices, perceptions and the incidence of speargrass were conducted in the forest and forest-savanna transition zones of Ghana in 1996 and 2000. Mean farm size was 1.2 ha, fallow and cropping length was 4.7 and 4.5 years, respectively, with a mean cropping intensity factor (CIF) of 49%. Speargrass had been present in the area for over 40 years and was perceived as the most noxious weed. Eighty- six percent of fields that relied on slash-burn method of land preparation had severe speargrass infestation. Infestations > 50% cover, mean density of 33 plants m-2 and shoot height range of 15–300 cm were observed on 60% of the fields. Fifty-one percent of farmers reported of inadequate level of control with current control practices. Glyphosate was applied on fields with > 50% speargrass cover. Speargrass becomes a problem after 3 years continuous cropping from fallow and, under severe infestation, most farmers abandon fields to natural fallow. A dense regrowth of Chromolaena odorata is indicative of a speargrass-suppressed field. Follow-up weed control could be 3-6 times/season depending on initial land preparation, type of crop and/or level of infestation. Cost of weed control was 20–60% higher on speargrass-infested field ($71/weeding/ha) than on other fields, and weeding may take 20–25 mandays/ha. Farmers perceived average yield losses of 30–80% ha–1 due to speargrass interference, implying a national average crop loss ha-1 of $31–$84, $155–$414 and $272–$727 for maize, cassava and yam systems, respectively. Reductions in food quality due to the piercing nature of the rhizomes was also paramount.

Soil and vegetation response to thinning White Cypress Pine (Callitris glaucophylla) on the North Western Slopes of New South Wales, Australia

Dense White Cypress Pine (Callitris glaucophylla J. Thompson and L.A.S. Johnson) regrowth occurs frequently across previously cleared landscapes in New South Wales (NSW), and is thought to adversely affect agricultural production and to cause land degradation. The NSW Native Vegetation Act (2003) requires that management of native vegetation including pre- 1990 regrowth must 'improve or maintain' site condition, yet there is currently limited informa- tion regarding techniques for the optimum man- agement of C. glaucophylla in this regard. We conducted a preliminary study to examine floristic composition, soil condition (to 50 cm) and carbon storage under 'Dense' (dense regrowth), 'Thin- ned' (dense regrowth thinned 2000/2001) and 'Un-colonised' (pasture not yet recolonised by C. glaucophylla) plots on private lands in NSW. Reduced tree density from thinning resulted in increased biomass of the remaining individual trees. Un-colonised plots had significantly more groundcover than thinned plots, which had sig- nificantly more groundcover than dense plots. Differences in plant diversity however, were ex- plained by site factors rather than land use. Soils in the dense plots were the most acid but soil pH was significantly higher in thinned plots and pH was highest in soil of the un-colonised plots. Mean values for carbon, nitrogen, sulphur and extract- able phosphorus varied among sites, although each were significantly more abundant in the mineral soil of dense and thinned plots compared with un-colonised plots, suggesting that thinning had had a minimal effect on the soil parameters assessed. Accounting for all site components, site carbon storage was significantly higher in dense and thinned plots compared with un-colonised plots due to elevated levels of soil and litter car- bon as well as the presence of trees. The results indicate that thinning dense C. glaucophylla can maintain and (by some measures) improve site condition. However, given the variability in some of the parameters assessed, further study across a wider range of soil types and rainfall gradients is proposed.

Ground Layer Competition and Herbivory Effects on Cherrybark Oak (Quercus pagoda Raf.) Regeneration in Experimental Canopy Gaps

COLLINS, BEVERLY (Savannah River Ecology Laboratory, Aiken, SC 29802). Ground layer competition and herbivory effects on cherrybark oak (Quercus pagoda Raf.) regeneration in experimental canopy gaps. J. Torrey Bot. Soc. 130:147-157. 2003. -Windthrows and small-scale forest harvests generate environmental heterogeneity and dense regrowth. In such sites, interactions among environmental factors, competition with ground layer vegetation, and herbivores attracted to the disturbed area all potentially influence recruitment and early establishment of canopy tree species. I examined the interactive effects of overstory gap size, canopy openness, herb layer competition, and mammalian (deer, swamp rabbits) herbivory on emergence and seedling bank formation of cherrybark oak, Quercus pagoda Raf., in experimental gaps created by mechanized logging in a bottomland hardwood forest. Acorns were planted in exclosures (deer, swamp rabbits, deer + swamp rabbits, neither) in the center of three gaps of each of six gap sizes (7, 10, 14, 20, 29, 40 m radius) and outside the exclosures in center, edge, and forest positions. Mortality was greatest during recruitment (within the first season), and was due primarily to damage to acorns by seed predators and shade effects on seedling establishment. After three seasons, seedlings from damaged acorns in the exclosure plots were shorter than those from undamaged acorns; however, these seedlings had higher relative growth rate, which suggests that acorn damage effects decline over time. Herb layer competition and shade due to position within a gap or gap size were associated with reduced survival or height of seedlings, both in the exclosures and in center, edge, and forest positions. Deer or rabbit herbivory had no measurable effect on seedling survival or growth over the first three seasons. Natural or created canopy gaps ' 14 m radius can be foci for Q. pagoda regeneration if acorns are protected from predators; however, the dense vegetation in regenerating gaps could limit seedling height growth and multiple openings may be necessary for ascent out of the seedling bank.

Disturbance, selective logging and bird diversity: a neotropical forest study

The composition and structure of bird communities, and the damage to forest structure were surveyed in northern French Guiana (northeastern Amazonia) one year and ten years after selective logging and compared with the situation in a similar undisturbed primary forest. A point-count method was used in which 937 0.25ha sample plots were censused for 20 minutes each, and their vegetation structure was measured. On average, 38% of the forest undergrowth was destroyed, then invaded by dense regrowth, and up to 63% of the canopy was substantially opened as a result of selective logging. Hunting pressure also increased due to access roads opened for logging. Among the 256 species recorded, overall bird species richness and abundance were depressed by 27–34% in the logged areas compared to primary forest. The most vulnerable guilds, which decreased by 37–98% in abundance, were mature forest understorey species, especially terrestrial ones and mixed flocks of insectivores. Hummingbirds, small gaps, vine tangles and canopy species did not decrease, nor increase significantly after logging. Only species naturally associated with dense second growth, forest edges and large gaps actually increased. Habitat specialization was the major determinant of vulnerability to logging, and, to a lesser degree, size (large) and diet (insectivorous), but foraging behaviour and rarity had little effect. Bird sensitivity to changes in logged forest structure may involve physiological intolerance, reduced food categories, increased exposure to predators, too dense understorey for their specific foraging behaviour and/or avoidance of gaps. Suggested improvements of current forest management and logging techniques for the maintenance of a higher proportion of the original biodiversity include minimizing logging damages, long rotations (>50 years) between cuts, and keeping unlogged forest patches within logging concessions.

Influence of Selective Logging on Bird Species Diversity in a Guianan Rain Forest

Abstract: The composition and structure of the bird community were investigated in French Guiana (northeastern Amazonia) 1 year and 10 years after selective logging and compared with bird community composition and structure in undisturbed primary forest. A point‐count method was used in which 937 0.25‐ha sample quadrats were censused for 20 minutes each. Whereas logging removed little more than 3 trees/ha, 38% of the forest undergrowth was destroyed and a proportion of the canopy was opened or damaged. An overall 27–33% decrease of species richness, frequency, and abundance occurred after logging, with a less marked decline of diversity and evenness indices, a substantial increase in the proportion of dominant species, and a 45% difference in species composition, weighed by frequency, between logged and undisturbed forest communities. Forty‐two percent of the species from the primary forest decreased sharply or disappeared after logging and only 34% increased or remained unchanged. Microhabitat selection was the main correlate of sensitivity to disturbance. Most affected by logging were species associated with the understory of tall mature stands especially terrestrial species, members of mixed flocks, and solitary sallying insectivores, all of which decreased by 70% to over 90%. Most birds associated with canopy, small gaps, and vine tangles declined by only 10–30%. Small frugivores and species associated with clearings or edges increased. Among other factors, physiological intolerance of understory species to open forest microclimatic conditions (light, heat, or water stress) might influence their avoidance of logged areas. Timber harvesting generated a high level of disturbance, which depressed the bird diversity. After over 10 years of regeneration, the dense regrowth produced a uniform habitat type that still had not recovered the high species richness exhibited by the primary forest under an intermediate level of disturbance.

AUSTRALIAN TRIAL OF TOPICAL MINOXIDIL AND PLACEBO IN EARLY MALE PATTERN BALDNESS

One hundred and sixty nine men with early male pattern baldness (androgenic alopecia) were treated in a random, double-blind fashion with either 2% minoxidil solution or placebo vehicle for 24 weeks, one ml applied twice daily. After 24 weeks all patients received the active solution until week 48. After 24 weeks the minoxidil treated patients had increased their non-vellus hair counts significantly more than the placebo treated group; means were 37.6 and 8.8 hairs per reference area, 95% C.I. for difference = 10.85 to 60.75. The rate of non-vellus hair regrowth was also greater among minoxidil treated patients than placebo treated patients. Nine (12.5%) evaluable minoxidil treated patients compared with 2 (2.7%) evaluable placebo treated patients reported moderate or dense hair regrowth at week 24. Minimal regrowth was reported by 18 (25%) active group and 15 (20%) placebo group patients. The investigators considered that 3 (2%) of the minoxidil group and none of the placebo group had moderate hair regrowth and that none had dense regrowth. After 48 weeks treatment 28 (23%) patients considered that they had moderate hair regrowth and the investigators considered that 14 (12%) patients had moderate regrowth. None had dense growth. No serious adverse reactions or deaths were reported. Minoxidil solution appeared to be an efficacious and safe treatment for early androgenic alopecia.

Habitat of the white‐footed dunnart Sminthopsis leucopus (Gray) (Dasyuridae: Marsupialia) in a logged, burnt forest near Bega, New South Wales

AbstractIn the winter of 1981, 9 months after an intense fire in November 1980 in the recently logged Mumbulla State Forest, the numbers of a small population of Sminthopsis leucopus had slightly increased, while the common species of small mammals had declined sharply from the previous winter. The study reported in this paper aimed to identify the habitat of S. leucopus. Ninety study plots were divided equally among three classes of forest (unlogged forest, and forest logged in 1979 and 1980), between two aspects (north‐ and south‐facing slopes), and among three topographic positions (ridge, midslope and gully). Plots were assessed on the basis of both floristic data and the structural components of ground, shrub and tree cover. The primary finding was that the habitat of S. leucopus was the treeless ridges and mid‐slopes with less than 51% ground cover in the logged areas of burnt forest. The floristic analysis showed that the vegetation subcommunities restricted to gullies, or carrying a ferny ground layer of vegetation, were not selected by S. leucopus. An analysis of movements of male S. leucopus identified two classes. ‘Resident’ males occurred on logged ridges and midslopes characterized by a floristic subcommunity of open forest with a grassy understorey.‘Explorer’ males moved through a variety of ridge habitats, including unlogged forest, and were spread more widely through the floristic communities. The pattern of habitat selection identified in this study shows S. leucopus to be ecologically distinct from the other species of small mammals in the forest and thus in need of special consideration in management programmes if it is to be conserved. Under the current regime, the uniform treatment of the forest leads to widespread stands of dense regrowth to the exclusion of the species and is inimical to its survival.

Population-Changes in Sminthopsis-Leucopus (Gray) (Marsupialia, Dasyuridae), and Other Small Mammal Species, in Forest Regenerating From Logging and Fire Near Bega, New-South-Wales

A population of the white-footed dunnart Sminthopsis leucopus was studied from 1981 to 1983 in a forest that had been logged in 1979, burnt in 1980, and was drought-affected throughout the study. S. leucopus bred in this disturbed habitat but did not persist when the vegetation regrew and became dense. Pouch young were present in August, September and October 1981. There was no evidence of polyoestry in the field, although breeding potential may have been suppressed by a combination of the drought and habitat change. There were few brown antechinus Antechinus stuartii present at any time. The population of the bush rat Rattus fuscipes increased as its preferred habitat of dense vegetation grew. An irruption of the house mouse Mus rnusculus in autumn 1982 coincided with a brief respite from the drought. The differing responses of these species to the same set of environmental conditions illustrates that no one management option in such forests will be optimal for all species of small mammals. The conclusion drawn here for the conservation of S. leucopus in forests subject to woodchip logging and fire is to stagger the forestry operations to ensure that not all parts of the forest are covered with dense regrowth at any one time.

The North Maroondah Experiment Pretreatment Phase comparison of catchment water balances

The North Maroondah Experimental Area contains a series of controlled catchment experiments which have the two major objectives of investigating the effects on long-term streamflow yields of reducing the density of existing 1939 regrowth mountain ash ( Eucalyptus regnans), and controlling the density of planting or sowing at the time of establishment of new stands. The aims of the analysis described in this paper are to examine the relationships between catchment water balances and catchment characteristics for the pretreatment period, and to identify any atypical catchments. An intercatchment comparison of twelve regrowth catchments based on an analysis of covariance of annual streamflow and catchment loss (i.e. catchment rainfall minus streamflow) identified two catchments which are losing water, and one collecting water from outside its topographic boundaries. Further statistical analyses of data from the nine typical regrowth catchments detected significant relationships between average catchment loss, radiation index and basal area of regrowth forest on the catchment. Catchment loss increased with both radiation index and basal area. The results indicate that if a thinned forest behaves in the same way as a natural forest with low basal area increases in streamflow resulting from thinning would be important from a water supply point of view. A comparison of the nine typical regrowth and two old growth catchments showed that the old growth catchments had significantly lower catchment loss. Further analysis showed that there was a significant relationship between annual catchment loss and stocking rate of trees for the eleven catchments. The decrease in streamflow which would result from conversion of an open old growth forest (20 trees/ha) to a dense regrowth forest (400 trees/ha) is of the order of 100–200 mm which is also important from a water supply point of view.

A NEW RECORD OF THE BUTTERFLY DODONIDIA HELMS1(Fereday)FOR THE WELLINGTON DISTRICT

Hudson records Dodonidia helmsi from the Tararuas, Silverstream, and the Eastern Harbour. This is a record of the capture of two specimens of this butterfly in Whiteman's Valley in February, 1963. On February 2nd the first specimen was caught a s i t flew along a track a t the head of the Mangaroa Swamp. It was a hot still day and the time was about 1 p.m. The bush in this locality was originally hard beech, Nothofagus truncata (Colenso), but has been milled recently and now consists mainly of dense regrowth (Kamahi, Weinmannia racemosa (Linn6) , Fivefinger, Neopanax arboreum (Murray) etc.) with a few remaining beech trees. The area has a n easterly aspect a n d is shaded f o r a greater par t of the day. The butterfly was first seen hovering in a patch of sunlight about 8 f t f rom the ground and occasionally alighting on sunlit leaves nearby. I t was on one of these leaves, about 5 f t f rom the ground, that the butterfly was caught. The second specimen was captured on February 8th about half a mile south of the Blue Mountains settlement, Whiteman's Valley, on a westerly aspect. The bush here has also been Nothofagus truncata as in the first case, although all tha t remains now is Manuka (Leptospermum sp. (Forster) ) scrub and isolated patches of beech. The butterfly was feeding on ornamental daisies in a garden about 10 yards from the scrub. The time of capture was approximately 5.30 p.m.; the area was still in the sun and there was no wind blowing. Both specimens were identified a s Dodonidia helmsi from Hudson and my identification was confirmed by Professor Salmon a t Victoria University. Both insects were believed to be females. Hudson states that the caterpillars feed on the sedge Gahnia setifolia (Hooker f.) and although sedges of this genus a re present in both localities no caterpillars or eggs were found in spite of s special search. The fac t that the two localities a r e about 1 mile apar t and separated by a n 800 f t hill indicates that these butterflies may be fairly widespread in this district, although no record appears t o have been made since 1928.