Density Of Mature Trees Research Articles

Effects of road age on the structure of roadside vegetation in south-eastern Australia

In many agricultural landscapes, roadside (or road verge) environments provide important refuge for threatened native species and ecosystems, and are often selected as benchmark sites to guide restoration activities. However few studies have investigated potential temporal variability in roadside vegetation conditions. In this paper we used archived cadastral maps to determine road age and examine potential variability in roadside vegetation structures in a typical rural landscape in south-eastern Australia. We found significant differences in the density of mature trees for road segments in different road-age categories. The oldest roads (<1870s) were characterized by having the greatest density of large hollow-bearing Eucalyptus trees, but few native conifer trees or shrubs. Roads surveyed when broad-scale clearing commenced (1870–1879), and not the oldest roads, were found to be more intact in terms of the density of large pre-settlement trees, range of tree stem-size classes and overall shrub diversity. By contrast, the youngest roads (post-1900s) had the greatest number of native conifer trees, but few shrubs or large Eucalyptus trees. As a result, roads of different ages had different densities of hollow-bearing trees, which is discussed in terms of past land-use legacies. These results have important implications for selecting roadsides as benchmark sites for restoration activities, and highlight the critical importance of roadsides to conserving native biota in agricultural landscapes.

Overstorey tree density and understorey regrowth effects on plant composition, stand structure and floristic richness in grazed temperate woodlands in eastern Australia

As natural woodlands decline in both extent and quality worldwide, there is an increasing recognition of the biodiversity conservation value of production landscapes. In low-input, low-productivity grazing systems in Australia, the modification of natural woodlands through overstorey tree and woody regrowth removal are vegetation management options used by landholders to increase native grass production for livestock grazing; however, there is little empirical evidence to indicate at what tree densities biodiversity attributes are compromised. We examined the effects of overstorey tree density and understorey regowth on the floristic composition, stand structure and species richness of eucalypt woodlands in a grazing landscape in the Traprock region of southern Queensland, Australia. We sampled 47 sites stratified according to vegetation type ( Eucalyptus crebra/Eucalyptus dealbata woodland; Eucalyptus melliodora/Eucalyptus microcarpa grassy woodland), density of mature trees (<6 trees/ha; 6–20 trees/ha; >20 trees/ha), and presence/absence of regrowth. Distinct patterns in composition were detected using indicator species analysis and non-metric multidimensional scaling, with low density areas compositionally indistinguishable, although distinct from other land management units. Within vegetation type, medium tree density woodlands were compositionally similar to high density and reference woodlands. Species richness ranged from 18 to 67 species per 500 m 2 across all sites. No differences in total or native species richness were detected across management units; however, some differences in exotic species richness were detected. Differences in grass cover existed between low and high density management units, yet no difference in grass cover was evident between low and medium density management units. Our results suggest that medium tree densities may provide biodiversity benefits concordant with more natural areas, yet not adversely impact on pasture production. Retaining trees in grazing landscapes provides significant landscape heterogeneity and important refuges for species that may be largely excluded from open grassland habitats. Maintaining a medium density of overstorey trees in grazed paddocks can provide both production and biodiversity benefits.

LONG-TERM VEGETATION DYNAMICS IN A CUT WESTERN JUNIPER WOODLAND

Abstract Western juniper (Juniperus occidentalis spp. occidentalis Hook.) expansion in the northern Great Basin has reduced shrubsteppe productivity and diversity. Chainsaw cutting of western juniper woodlands is commonly applied to remove tree interference and restore sagebrush plant communities. Studies assessing understory response following cutting have been limited to early successional stages and have not evaluated the effects of western juniper debris on plant succession. Cutting western juniper produces a large amount of debris which is commonly left on site, occupying a significant portion of treated areas. This study evaluated successional dynamics spanning 13 years after western juniper cutting. Four 0.45-ha blocks were selected on Steens Mountain in southeastern Oregon. Western juniper cover averaged 26% and mature tree density averaged 250 trees · ha−1. Blocks were cut in late summer 1991. Understory standing crop, cover, and density were compared among 3 locations: old canopy litter mats (ca...

Effects of management and time on mechanisms of bush encroachment in southern Ethiopia

Bush encroachment poses a threat to livestock management in southern Ethiopia. Despite this, the mechanisms of bush encroachment in response to protection and the time of protection compared with continuous grazing are rarely investigated. In this study, we used the state-and-transitional model (STT) to investigate the mechanisms of bush encroachment using six traditional enclosures along age chronosequences of 12-14, 17-24 and 26-30 years compared with open grazed system immediately adjacent to each enclosure (as control). The woody vegetation was sampled by randomly locating 10 plots (5 x 5 m) in each of the six enclosures and the adjacent open grazed areas. We compared the enclosure management with the open grazed system in terms of densities of mature trees, saplings and seedlings, bush cover, woody species composition, and the invasive woody species ratio (IWSR). The IWSR is the ratio of density of invasive woody species to non-invasive woody species (i.e. a ratio of >1.0 represents a high invasive threat, while <1.0 represents a lesser threat). We considered the future responses of invasive species by increasing the age of enclosures. We identified five vegetation states and ten transitions described in terms of densities of mature trees, saplings and seedlings, bush cover, woody species composition, and the IWSR. Greater densities of invasive woody species and higher IWSR were found in the enclosures than in the open grazed system, but this was not true for bush cover. Doubling the age of enclosures had a negative impact on the majority of invasive woody species, the decline probably being related to self-thinning mortality. The evidence that regeneration of invasive woody species is nonlinear in relation to age chronosequence suggests that bush encroachment is probably controlled more by stochastic rainfall events than by livestock grazing alone. Vegetation states differed in terms of tree density, IWSR and species composition, suggesting that the threat of invasive woody species is greater in the enclosures than in the open grazed areas.

Caribou nursery site habitat characteristics in two northern Ontario parks

To prevent further range recession, habitat features essential to the life-history requisites of woodland caribou (Rangifer tarandus caribou) such as calving and nursery sites need to be protected for the persistence of the species. Woodland caribou may minimize predation risk during calving by either spacing out or spacing away from predators in the forest to calve on islands, wetlands, or shorelines. Our objective was to determine the characteristics of shoreline habitats used as calving and nursery sites by female woodland caribou in northern Ontario. Detailed vegetation and other site characteristics were measured at nursery sites used by cow-calf pairs in Wabakimi and Woodland Caribou Provincial Parks for comparison with shoreline sites that were not used by caribou within each park. Differences in habitat variables selected by female caribou in the two study areas reflect broad ecoregional differences in vegetation and topography. In Wabakimi Provincial Park, understorey tree density and ground detection distance played key roles in distinguishing nursery sites from sites that were not used. In Woodland Caribou Provincial Park, groundcover vegetation and shrub density were important in the selection of nursery sites by female caribou. Generally, female caribou in both parks selected nursery sites with greater slope, lower shrub density but thicker groundcover vegetation, including greater lichen abundance, and higher densities of mature trees than shoreline sites that were not used. The identification of these important features for caribou nursery sites provides a basis for improving their protection in future management policies and legislation.

Effects of flowering tree density on the mating system and gene flow in Shorea leprosula (Dipterocarpaceae) in Peninsular Malaysia

Pristine tropical rainforests in Southeast Asia have rich species diversity and are important habitats for many plant species. However, the extent of these forests has declined in recent decades and they have become fragmented due to human activities. These developments may reduce the genetic diversity of species within them and, consequently, the species' ability to adapt to environmental changes. Our objective in the study presented here was to clarify the effect of tree density on the genetic diversity and gene flow patterns of Shorea leprosula Miq. populations in Peninsular Malaysia. For this purpose, we related genetic diversity and pollen flow parameters of seedling populations in study plots to the density of mature trees in their vicinity. The results show that gene diversity and allelic richness were not significantly correlated to the mature tree density. However, the number of rare alleles among the seedlings and the selfing rates of the mother trees were negatively correlated with the density of the adult trees. Furthermore, in a population with high mature tree density pollination distances were frequently <200 m, but in populations with low adult tree density the distances were longer. These findings suggest that the density of flowering trees affects selfing rates, gene flow and, thus, the genetic diversity of S. leprosula populations. We also found an individual S. leprosula tree with a unique reproductive system, probably apomictic, mating system.

The interaction of seedling density dependence and fire in a matrix population model of longleaf pine ( Pinus palustris)

Longleaf pine ( Pinus palustris) forests once dominated much of the southeastern USA, but have been reduced to a small fraction of the original range through human activities during the past 200 years. Successful restoration of longleaf pine populations depends on managing fire frequency and stand densities. In order to investigate the interactions between fire frequency and density dependence, we incorporated four functions relating seedling establishment and survival to mature tree density in a matrix population model. Under a regime of frequent fires (FF; once in each 4-year time step), longleaf pine population dynamics were relatively insensitive to the form of density dependence. With fire return times longer than 4 years, the stability of the population (based on the deviation of population size from the FF equilibrium) was highest with density-dependent functions that had the least effect on seedlings at low density. The dominant eigenvalues ( λ) of the density-independent matrix models (using the maximum values for fecundity and seedling survival) were related to the rate of approach of the density-dependent model to equilibrium. Models with convex or linear shaped density-dependent functions showed evidence of chaotic-type dynamics at higher growth rates, however the least stable model (based on the deviation of the infrequent fire regime population size from the FF equilibrium), using a concave Beverton-Holt density-dependent function, had a monotonic approach to equilibrium even at an unrealistic λ of 2.50. The interaction of fire and mature tree density on longleaf pine seedling establishment and survival must be accurately determined in order to properly simulate these populations.

Marsh Tit Poecile palustris territories in a British broad‐leaved wood

We used individual colour‐marking and territory mapping to quantify the spatial extent of 32 Marsh Tit Poecile palustris territories in Monks Wood, eastern England, during spring of the years 2002–04. A mean territory size of 4.1 ha was identified. All 2004 spring territories were located, allowing a breeding density of 14 pairs/km2 to be calculated. Availability of airborne digital remote sensing (LiDAR) data for Monks Wood allowed the characterization of the canopy structure in territories and non‐breeding areas using a three‐dimensional canopy‐height model. The difference between the mean canopy height of the 2004 territories and that of the unoccupied area of the study site in the same year was 1.8 m, or 14%. Sampling the unoccupied area, with hypothetical ‘pseudo‐territories’, showed a statistically significant difference of 1.6 m (13%) between the mean canopy heights of the ‘taller’ 2004 territories and the unoccupied pseudo‐territories. A comparison by field survey of tree and shrub species composition between the 2004 territories and pseudo‐territories found no difference in species richness or the mean density of shrubs or mature trees (&gt; 30 cm diameter at breast height, dbh). The mean density of medium‐sized (5–30 cm dbh) and small (&lt; 5 cm dbh) trees was, respectively, 1.9 and 3.9 times greater in the pseudo‐territories, values that were statistically significant. Overall, Marsh Tits in Monks Wood appeared to require mature trees with a shrub layer beneath the top canopy, but avoided areas with large numbers of young and immature trees.

Sapling Structure and Regeneration Strategy in 18 Shorea Species Co-occurring in a Tropical Rainforest

Inevitable trade-offs in structure may be a basis for differentiation in plant strategies. Juvenile trees in different functional groups are characterized by specific suites of structural traits such as crown architecture and biomass distribution. The relationship between juvenile tree structure and function was tested to find out if it is robust among functionally and taxonomically similar species of the genus Shorea that coexist sympatrically in a tropical rain forest in Borneo. The sapling structures of 18 species were compared for standardized dry masses of 5 and 30 g. Pairwise simple correlation and multiple correlation patterns among structural traits of juveniles (0.1-1.5 m in height) of 18 Shorea species were examined using Pearson's correlation and principal component analysis (PCA), respectively. The correlation was then tested between the PCA results and three indices of shade tolerance: the net photosynthetic rate, the wood density of mature trees and seed size. The structural variation in saplings of the genus Shorea was as large as that found in sets of species with much more diverse origins. The PCA showed that both crown architecture and allocation to leaves are major sources of variation in the structures of the 18 species investigated. Of these two axes, allocation to leaves was significantly correlated with wood density and showed a limited correlation with photosynthetic rate, whereas crown architecture was significantly correlated to seed size. Overall, the results suggest that an allocation trade-off between leaves and other organs, which co-varied with wood density and to a certain extent with photosynthetic capacity, accounts for the difference in shade tolerance among congeneric, functionally similar species. In contrast, the relationship between the architecture and regeneration strategy differed from the pattern found between functional groups, and the function of crown architecture was ambiguous.

Processing 17-year-old Tasmanian blue gum sawlogs grown at wide spacing

Summary Large areas of Tasmanian blue gum (Eucalyptus globulus Labili, subsp. globulus) have been planted in the south-west of Western Australia. This resource is principally planted on farmland for pulp and paper manufacture, but a small proportion has been managed for sawlogs. In this study a sample of logs from a 17-y-old Tasmanian blue gum stand grown on an ex-bush site, and thinned and pruned at an early age, was processed into sawn timber. Mean sawlog small-end-diameter-under-bark was 39.3–45.6 cm. The recovery of appearance-grade boards, based on log volume, was 30%, and another 2.4% could be used as filler laminates in panels or panel products. Mean air-dry density was estimated to be 680 kg m−3, similar to the density found in other studies, but lower than the density of mature trees. Recovery and wood quality are compared with those obtained in other studies conducted in Western Australia and the eastern States. The development of a new eucalypt sawlog industry on cleared private land is discussed.

Effects of land-use and landscape structure on holm oak recruitment and regeneration at farm level in Quercus ilex L. dehesas

Successful regeneration of holm oaks is essential for the maintenance of biological diversity in the dehesas of Central Spain. In order to explore land-use and ecological site determinants of holm oak regeneration, we conducted a survey of oak recruitment and regeneration, physical features, and grazing impact indicators through a variety of sampling methods. Juvenile and sapling abundance was alarmingly low (51.2±69.1 and 85.0±85.2 plants ha −1), but varied considerably within and across study sites. Statistical analysis of spatial distribution of juveniles and saplings showed that they were highly clumped ( t N=0.64 and 0.61), while mature trees were dispersed uniformly ( t N=0.38). The clumping of juveniles and saplings results from the tendency for regeneration to occur on safe microsites protected from browsing and radiation (shrubs and next to rock outcrops) or from the capacity of ramets to grow vegetatively underneath canopies. We developed indicators for grazing pressure, but none of these showed any relationship with vegetation variables. Crop cultivated dehesas had lower mature tree densities (18.9±13.9 trees ha −1) than grazed (38.6±18.1 trees ha −1) and shrubby (56.4±27.5 trees ha −1) dehesas, indicating potentially negative consequences of cultivation on holm oak demography. Abundant oak regeneration was correlated with mature tree density and size, with woody vegetation cover, and with physical features such as slope, rock cover, and paddock extent. These results suggest that holm oak regeneration in dehesas is controlled by physiognomic features and long-term human impacts rather than directly by current grazing levels.

Agroforestry adoption in Haiti: the importance of household and farm characteristics

Most agroforestry-adoption studies are based on surveys of non-adopters. An understanding of the circumstances that have led to a change of attitude of the adopters will be valuable in our efforts to enhance adoption rates. This study was undertaken to provide such knowledge based on a large agroforestry extension project involving 200,000 farm families and covering 25% of all rural households in Haiti. A questionnaire-based survey of the project participants was conducted covering 1,540 households and 2,295 fields in four regions of Haiti. Information was recorded about each farm and family member through interviews with farmers and visits to their farms. The results confirmed that farmers make decisions about tree culture based on household- and field characteristics. Different farmers consider trees differently depending upon how they fit into their farm-family strategy. In general, farmers installed tree hedgerows on fields of less secure tenure, of lesser fertility, and steeper slope, while on closer, more fertile fields of greater tenure security, tree seedlings and fruit trees were more common and there was a greater density of mature trees (>10 cm DBH). More money was realized from sale of tree products on actively cropped fields in more secure tenure and having more fertile soil. Older farmers managed a greater density of trees, especially when the land was in secure tenure status. This broad-based study shows that agroforestry implementation strategies in poor countries such as Haiti should be based on a thorough knowledge of how farmers use household and field characteristics to make adoption decisions. It also suggests that agroforestry-adoption studies should account for the dynamic changes occurring during extended time periods.

Soil seed flora, germination and regeneration pattern of woody species in an Acacia woodland of the Rift Valley in Ethiopia

The objectives of this study were to determine the composition, density and spatial distribution of the soil seed bank of woody species, as well as their regeneration pattern in two different land use systems, controlled (ranch) and open grazing, in an Acacia woodland of the Rift Valley in Ethiopia. We also compared the species composition of the soil seed bank and the above-ground vegetation to find out if differences exist in the soil seed bank and advance regeneration between the two land use systems. The germination requirements of seeds of the woody species were also investigated under laboratory conditions. Acacia senegal, Acacia seyal, Acacia tortilis, Dichrostacys cinerea and Balanites aegyptiaca were encountered in the above-ground vegetation in both systems. Seeds of only A. tortilis (90±32 seeds m−2) from the ranch, and A. senegal (5±3 seeds m−2) and A. tortilis (72±34 seeds m−2) from the open system were found in the soil seed bank along transects with patchy horizontal pattern. The two systems were not significantly different in density of soil seed banks of A. senegal andA. tortilis . Jaccard's similarity index showed that only a few woody species were common in the soil seed flora and above ground vegetation. However, all of the species accumulated seeds (58±43–331±130 seeds m−2) in/on the soil under the canopy. Very large numbers of seeds of A. tortilis (19382±9722 seeds m−2) and D. cinerea (1278±494 seeds m−2) were also found in barns. Most of the seeds recovered from the soil samples (60–80%) were found in the litter layer. Acid and mechanical scarification improved legume germination (36–99% and 60–99%, respectively) over boiling water (0–48%). Treatment means differed significantly for all the legumes (p<0·001) but not for Balanites. Height and diameter class distribution of regeneration of A. tortilis and D. cinerea in both systems and A. senegal in the open system had a negative exponential correlation (rs=−0·5, −0·25 and −0·86, respectively). A. seyal and B. aegyptiaca showed poor regeneration. Horizontal distribution of advance regeneration of all the species was patchy. Advance regeneration of A. seyal, A. tortilis and B. aegyptiaca were not significantly different, while that of A. senegal and D. cinerea were significantly different between the two systems. Poor representation of species in the soil seed bank along transects and in the different height and diameter classes may be attributed to the low density of mature trees as well as the mode and strategy of seed dispersal. Ungulate and wind dispersed species (e.g. A. senegal, A. tortilis and D. cinerea) were highly favoured. Patchiness in the distribution of seeds and advance regeneration was also a result of endozoochory. Dispersal of non-ungulate dispersed seeds (A. senegal, A. seyal and B. aegyptiaca) was restricted to the canopy zone. Piles of seeds ofA. tortilis and D. cinerea that were found in barns were a result of consumption of their pods by cattle. High concentration of seeds in the litter layer may be due to low soil disturbance and larger size of seeds. The height and diameter class distribution of A. senegal (in the open system), A. tortilis and D. cinerea also indicated that the species have good regeneration. Results from the germination tests indicated that seeds of the legumes require pre-sowing treatments to give a rapid, uniform and improved germination. Intervention through artificial regeneration should be employed to improve the density and regeneration capacity of those species with hampered regeneration at both systems.

Factors Related to the Recovery of Subalpine Woodland on Mauna Kea, Hawaii1

ABSTRACTWe measured mature tree and sapling density, tree associations, crown size, age structure, recovery from ungulate browsing, and grass cover at four study sites in two types of subalpine woodland on Mauna Kea volcano, island of Hawaii. Beginning in 1981, introduced ungulates were reduced in number to allow regeneration of Sophora chrysophylla (mamane) in habitat supporting the endangered Hawaiian finch, Loxioides bailleui (palila). We found Sophora regeneration at all four study sites, but regeneration was higher in mixed species woodland with codominant Myoporum sandwicense (naio) than in areas where Sophora dominated. Regeneration of Myoporum was uniformly very low in comparison. Invasive grass cover, which suppresses Sophora germination, was highest in mid‐elevation woodland where Sophora dominated. The distribution of mature and sapling Sophora were both related to study site, reflecting previous ungulate browsing and uneven recovery due to grasses. Densities of Sophora snags were not different among any of the sites, suggesting a more even distribution in the past. Selective browsing before ungulate reduction may have favored Myoporum over Sophora, leading to high densities of mature Myoporum in codominant woodland. After ungulate reduction, however, we found no pattern of competitive inhibition by Myoporum on regeneration of Sophora. Reduction of Myoporum is not likely to enhance habitat for Loxioides as much as supplemental plantings of Sophora, glass control, and continued ungulate eradication. Mid‐elevation Sophora woodland areas, where Loxioides forage and nest in high densities, would benefit the most from these management actions.

Ecology and management of sacred groves in Kerala, India

In Kerala, based on management systems, sacred groves can be categorised into three groups namely those managed by individual families, by groups of families and by the statutory agencies for temple management (Devaswom Board). Ollur Kavu, S.N. Puram Kavu and Iringole Kavu which represent above mentioned management systems, respectively, were studied for their tree species composition and vegetation structure. The study was also designed to assess the strengths and weaknesses of present management systems and role of different stakeholder groups in conserving the sacred groves. Of the three sacred groves, the one managed by individual family (Ollur Kavu) is highly disturbed as indicated by low stem density of mature trees (367 ha −1) and poor regeneration potential with the ratio between mature trees and saplings is 1:0.4. In order to quantify the level of disturbance in these sacred groves, Ramakrishnan index of stand quality (RISQ) was calculated. The values obtained for all the three tree layers (i.e., mature trees, saplings and seedlings) in single family managed sacred grove (Ollur Kavu) was between 2.265 and 2.731, an indicator of the dominance of light demanding species in the population, suggested that the grove is highly disturbed one. Whereas, other two sacred groves are less disturbed as indicated by lower `RISQ' values (between 1.319 and 1.648). Iringole Kavu and S.N. Puram Kavu were compared with some other evergreen forests of the Western Ghats of India for the parameters like stem density, basal area and species diversity of trees (gbh≥10.1 cm). Values obtained for these parameters in the two sacred groves are within the range obtained for other forests. Stakeholder importance value index (SIVI) was calculated based on the attributes like the proximity of the stakeholder to the sacred grove, contribution of stakeholders in managing the sacred grove, benefits being enjoyed by the stakeholder due to involvement with sacred grove and attitude of the stakeholder group towards the conservation and management of sacred grove. This indicated that local people, temple trust and/ or sacred grove owners are the major stakeholders, while in general some other stakeholder groups such as youth clubs, schools, forest department, municipality and local Panchayat with lower SIVI are comparatively neutral in conserving and managing the groves. Some of the major strategies to be adopted are self-imposed complete ban on the removal of biomass for the revitalisation of ecosystem, creation of awareness among local people and all stakeholder groups, identification of the type of contribution a stakeholder group can offer in managing the sacred grove and encouragement of all stakeholders to participate without either directly or indirectly adversely affecting the ecosystem as well as the wisdom and interest of the major stakeholder groups.

SEED DISPERSAL AND SEEDLING RECRUITMENT OFBETULA ALLEGHANIENSIS: SPATIAL INCONSISTENCY IN TIME

Recruitment in plants is the result of several processes operating from the time the seeds are mature and ready to be released from the parent plant to the time the seedlings emerge and become photosynthetically self-sufficient. In most species of strongly seasonal climates (e.g., trees of the cold temperate forests of North America and Japan), seed dispersal and seedling establishment are processes separated in time by at least a few weeks and more typically by a few months. This leaves ample opportunity for various factors to affect the spatial patterns of seed dispersal, survival and germination, and seedling emergence. Spatial uncoupling between these sequential processes leads to spatial independence (i.e., absence of a relationship) in the abundance patterns of life stages. Along a topographical gradient in an old-growth cold temperate forest of northeastern North America, I analyzed the spatial patterns of seed rain, seed bank, and seedling emergence of a major tree component, Betula alleghaniensis, over a 4-yr period. I examined the degree of consistency through time of the spatial patterns of each life stage and of their relationships with one another. Seed rain and seedling spatial patterns were quite variable through time, but that of the seed bank was relatively consistent despite large interyear fluctuations in abundance. Overall, two major spatial patterns emerged along the topographical gradient: one that emphasized the three peaks of density of mature Betula trees, and one with a single peak in the middle section of the gradient, where Betula tree density was higher. Correlations between the spatial patterns of seed and seedling abundance were significant in some years, but not in others. Seed survival was practically constant in space in one year, but quite variable in another; yet, it was consistently density independent. Spatial uncoupling was important between processes as reflected by the spatial independence between life-stage abundance patterns. This uncoupling significantly contributes to the spatiotemporal heterogeneity of the system and complicates fine-scale modeling of population and community dynamics.

Manejo silvicultural em seringais nativos, na microrregião Alto Purus-Acre

Resumo Através de manejo silvicultural em seringais nativos na microrregião do Alto Purus-AC, conseguiu-se um aumento na densidade de seringueiras em corte por estrada no seringal Pirã de Rã, localizado na antiga estrada de Boca do Acre, no Município Guiomard Santos, a 31 km de Rio Branco. Com tal aumento será possível reduzir em parte um dos principais fatores do alto custo da produção de borracha nos seringais nativos, que é a baixa densidade de árvores em corte.