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1.
We analyzed the role of regeneration type (surviving from advanced regeneration, resprouting from advanced regeneration, or
newly recruited seedlings) in determining the quantity and quality of individuals in reestablishing a natural forest following
clear-cutting of a conifer plantation. We experimentally clear-cut a plantation and undertook a detailed tree census before
and after clear-cutting. After clear-cutting, a species composition partially representing warm-temperate evergreen broadleaf
forest was present in the form of surviving and resprouted individuals originating from advanced regeneration that had established
in the Chamaecyparis obtusa plantation. On the other hand, seedlings that established after clear-cutting were dominated by pioneer species, and the
number of seedlings was far greater than the number of individuals originating from advanced regeneration. Our results suggest
that the role of regeneration type would differ in relation to the objectives for forest recovery. When any kind of woody
cover of the ground surface after clear-cutting would suffice, we suggest that the contribution of pioneer seedlings originating
from buried seeds would be important. If the recovery objective is to form a simple evergreen broadleaf forest, such as a
coppice woodland, all three sources of regeneration would play a similar role, provided the understory before clear-cutting
was as well developed as the one in this study. If rapid establishment of a lucidophyllous forest with diverse species composition
is desired, the role of the surviving and resprouting individuals originating from the advanced regeneration would be much
more important. 相似文献
2.
Key message
In the African rim of the Western Mediterranean Basin, cork oak forests and pine plantations coexist. Under similar fire regimes, cork oak forest is more resilient in terms of habitat structure (canopy, understory, and complexity of vegetation strata) than pine plantation. By contrast, both woodland types show similar resilience in plant species composition. Resilience in habitat structure varies between the two woodland types because of the resprouting and seeding strategies of cork oak and pine species, respectively. These differences can be relevant for the conservation of biodiversity of forested ecosystems in a future scenario of increased fire frequency and scale in the Mediterranean basin.Context
Wildfires have major impacts on ecosystems globally. In fire-prone regions, plant species have developed adaptive traits (resprouting and seeding) to survive and persist due to long evolutionary coexistence with fire. In the African rim of the Western Mediterranean Basin, cork oak forest and pine plantation are the most frequently burnt woodlands. Both species have different strategies to respond fire: cork oak is a resprouter while pines are mostly seeders.Aims
We have examined the hypothesis that pine plantations are less resilient in habitat structure (canopy, understory, diversity of vegetation strata) and plant composition than cork oak woodlands.Methods
The habitat structure and plant species composition were measured in 30 burnt and 30 unburnt 700-m transects at 12 burnt sites from north-western Africa, where the two forest types can coexist. Habitat structure and plant species composition were compared between burnt and unburnt transects from cork oak and pine plantation woodlands with generalized linear mixed models and general linear models.Results
The results showed significant interaction effect of fire and forest type, since cork oak forest was more resilient to fire than was pine plantation in habitat structure. By contrast, both forest types were resilient to fire in the composition of the plant communities, i.e., plant composition prior to fire did not change afterwards.Conclusion
The higher structural resilience of cork oak forest compared to pine plantation is related to the resprouting and seeding strategies, respectively, of the dominant tree species. Differences in the responses to fire need to be considered in conservation planning for the maintenance of the Mediterranean biodiversity in a future scenario of changes in fire regime.3.
A bark beetle (Ips typographus) infestation caused the death of almost all Norway spruce (Picea abies) trees in a mountain forest in the Swiss Alps. We developed a tree regeneration model, ‘RegSnag’ (=REGeneration in a SNAG stand), to project the future amount and height of tree regeneration in these snag stands. The model combines a height-class structured tree module with a microsite-based module of snag decay and ground-vegetation succession. Microsite-specific rates of germination, mortality and height growth were modelled for four tree species (Picea abies, Sorbus aucuparia, Acer pseudoplatanus and Betula pendula) in eight height classes (from seedlings to saplings 5 m tall) and on 26 microsite types (e.g. moss, grass). Model tests with independent field data from 8 years after the Picea die-back demonstrated that microsites had a considerable effect on the development of tree regeneration on both the montane and the subalpine level. With microsite-specific parameters, the height and frequency of Picea in each microsite could be simulated more accurately than without considering microsite effects (e.g. bias of 8 vs. 119 saplings ha−1 on the montane level). Results of simulations 40 years into the future suggest that about 330–930 Picea saplings per ha out of those that germinated in 1994 and 1996 will reach a height of 5 m within 30–35 years after Picea die-back. This is due to differences in seed inflow and browsing intensities. Picea and not Betula or Sorbus trees will replace the current herbaceous vegetation in these snag stands. 相似文献
4.
Yoshinori Tokuoka Kentaro Ohigashi Koji Watanabe Hiroshi Yamaguchi Takahiro Ara Nobukazu Nakagoshi 《林业研究》2016,27(6):1287-1294
Natural forest recovery on abandoned farmland is hindered by a variety of factors and active restoration plays an important role when quick afforestation is desired. We investigated seedling survival of four transplanted native tree species (Quercus myrsinifolia, Quercus serrata, Aphananthe aspera, and Rhus sylvestris) by experimentally manipulating the vegetation cover, which was mainly dominated by dwarf bamboo (Pleioblastus chino), and herbivore access to the planting sites on farmland that had been abandoned for 15 years at the start of the study. Few transplanted seedlings of any species survived under intact vegetation cover, irrespective of herbivore presence. In gaps in the vegetation cover, winter browsing by Japanese hare (Lepus brachyurus) damaged all species. However, lower browsing frequency and higher resprouting ability after grazing of the seedlings enabled both Quercus species to survive better than the other species. These results indicate that dwarf bamboo and the hare jointly limit the establishment of native trees in old fields. If active afforestation by transplanting seedlings at sites dominated by dwarf bamboo is planned, a combination of vegetation removal, selection of suitable species, and temporary seedling protection will be most effective. 相似文献
5.
Kauê de Sousa Guillermo Detlefsen Diego Tobar Elias de Melo Virginio Filho Fernando Casanoves 《Agroforestry Systems》2017,91(6):1119-1127
Silvopastoral systems—the management of trees within pastures from natural regeneration or planting—are a strategy to promote sustainable livestock systems and ecosystems services. Timber is one of the products from these systems with potential to increase family revenues. The management of natural regeneration and population dynamics of trees is a feasible way to harvest timber and maintain environmental services. In this research, we modeled the population dynamics of Pinus oocarpa and Tabebuia rosea, two important timber species of silvopastoral systems in Central America. The results showed that farmers manage a significant density of different tree species from natural regeneration. However, only the species with well-known uses or desired services are allowed to remain. The natural regeneration is more impressive in silvopastoral systems with natural grass than those with exotic grass. Farming practices, for instance use of fire for weed control, are the main reasons for low rates of natural regeneration in pastures with exotic grass. The models of population dynamics for both species showed that the sustainable timber harvest plans are a viable activity in pasturelands under natural-regeneration management plans. Innovative farmers are willing to adopt silvicultural practices and management of population dynamics to increase timber revenues and sustainability if forestry regulations for sustainable use of trees in farms are simplified. 相似文献
6.
Aspen (Populus tremuloides Michx.) is a foundational tree species of the North American boreal forest. After disturbance, clonal aspen stands quickly achieve canopy closure by sending up numerous clonal shoots (root suckers) from their lateral root system. Controlled aboveground disturbance will commonly induce prolific root suckering and thereby increase stem density in clonal aspen stands, but it is unclear if increases in stem density will be observed in planted seedling-origin aspen stands. The objectives of this study were to determine (1) overall root suckering response of planted aspen to aboveground disturbance; (2) if different cut heights of the stem or infliction of root damage impact the number of root suckers produced. We found that planted aspen regenerated readily after disturbance, averaging five root suckers per cut tree. However, individual response was highly variable, ranging from zero to 29 root suckers per root system. Of the cut trees, 75% produced at least one root sucker and 60% produced at least one stump sprout. Cutting trees close to the soil surface produced more root suckers than leaving a 25 cm stump. While root system size (mass and length) was well correlated with aboveground measures of planted aspen, root suckering was not related to root system size. As a result of increased forest reclamation efforts in the boreal forest region the planting of aspen has become a more common practice, necessitating a better understanding of the regeneration dynamics and root suckering potential of these planted and seedling-origin aspen forests. 相似文献
7.
For centuries, the Lacandon Maya have farmed the forest while also preserving and regenerating it. The Lacandon manage their
fallow by planting certain tree species, and removing volunteer trees that are not optimal for soil fertility. This study
focused on tao (Belotia mexicana), one of the Lacandon tree fallow species, and its impact on the soil as it matures in the secondary forest. The effect of
tao on soil fertility was evaluated using the following soil fertility parameters: phosphorus, carbon, nitrogen, earthworm density,
pH, and soil moisture. Results were compared using a split-plot analysis. Soil C:N ratios decreased with age of tao, indicating an improvement of litter quality over time. Soil extractable phosphorus decreased with age of tao and increased with distance from tao, which suggests that tao is depleting phosphorus. These results provide an introduction for further analysis into how native trees enhance soil fertility
in the Lacandon system. 相似文献
8.
9.
This study presents empirical data on regeneration and growth of understory trees and constructs simple models for predicting
these characteristics at various stand structure and post-thinning standing volume levels. The field experiment was established
on a grass/herb mineral soil site in central Finland. Regeneration and understory tree growth data were collected from 24
Norway spruce (Picea abies L.)-dominated mixed substands. Seedlings with heights from 5 to 130 cm were measured in 1996 and 2007. In addition, the annual
height growth of Norway spruce seedlings was measured in 2007. The spatial pattern of the substands varied from clustered
to regular with a decreasing standing volume. Stand complexity was uniform across the range of standing volume. In the 2007
survey, the amount of Norway spruce regeneration increased from approximately 400 to 5,000 seedlings ha−1 when the post-thinning standing volume level was reduced from 230 to 90 m3 ha−1, respectively. Nearly no seedlings were found when the standing volume was over 300 m3 ha−1. The annual diameter increment in Norway spruce understory (dbh < 5 cm) trees decreased, on the average, from 2.3 to 0.3 mm
with an increase in the standing volume level from 90 to 340 m3 ha−1, respectively; their height growth showed also a decreasing trend when the standing volume increased. The results indicated
that a post-thinning standing volume lower than 150 m3 ha−1 with a regular overstory spatial structure provides a suitable environment for regeneration and growth of Norway spruce understory
trees in the studied forest type. 相似文献
10.
The problem of salinized soils has become one of the most serious constraints to agricultural and forest productivity. With the purpose of enhancing salt stress tolerance of Populus tomentosa, we transformed this tree species with spermidine synthase （SPDS） genes derived from an apple by an Agrobacterium-mediated method. Four transgenic clones were confu＇med by PCR and Southern blot analysis. As well, the expression of introduced SPDS genes was analyzed by real-time quantitative PCR. 相似文献
11.
The success of tree plantings in agricultural landscapes within dry and variable rainfall regions is often below expectations.
The aims of this study were to investigate techniques for establishing a local native species (Eucalyptus pauciflora) and an exotic species (E. nitens) in the Midlands of Tasmania, a tree-denuded region that has been grazed for over 100 years in Australia. We established
trials at the Sorrel Springs and Woodland Park properties. We compared six establishment techniques: control; understorey
nurse planting; spot burn; mulch; tree-guard and; self-watering tree-guard. Three months, 1 and 6 years after planting we
measured tree height, health index and mortality. At Sorrell Springs tree-guarded treatments had greater height than other
treatments at year one, but there were no effects of treatment at year six on height, health or mortality. At Woodland Park
mulch, burn and tree-guarded treatments had greater height 1 and 6 years after planting. At year six tree-guarded treatments
had lower mortality than other treatments. At Sorrell Springs height of E. nitens was greater than E. pauciflora at year one but not at year six. At Woodland Park height of E. nitens was generally greater at year six but having almost double the incidence of mortality relative to E. pauciflora. We conclude that expensive tree-guarding is only warranted where high browse pressure is expected and that on such sites
species with tough leaves that are resistant to browsing should be considered. Further that in environments marginal for growing
trees, best practice establishment technique is generally as effective as additional treatments of understorey nurse planting,
spot burning or mulching. 相似文献
12.
Natural forests have been increasingly replaced by artificial plantations around the world. Some research results suggest
that artificial plantations can promote natural regeneration. The efforts in establishing protective forests in Hong Kong
over the last 50 years after the Second World War have resulted in many exotic tree plantations which are ideal sites for
the study of natural regeneration. This study looked at the seed rain and understorey woody plant diversity in three Lophostemon confertus plantations (25–40 years old) in Hong Kong. All the plantations were > 1 km from the nearest seed sources. Two of the plantations
had a seed rain comparable in density and diversity to unplanted grasslands, and the understorey plant diversity was also
low and dominated by shrubs. The other site had a higher and more diverse seed rain, as well as higher understorey stem density,
but both the seed rain and the understorey were dominated by the shrub Psychotria asiatica. The poor seed rain at two sites and the rarity of potential canopy tree species in both the seed rain and understory regeneration
at all sites suggest that planting exotic monocultures does not promote succession. Enrichment planting will be needed to
restore forest diversity. 相似文献
13.
14.
Herwig Ruprecht Amalesh Dhar Bernhard Aigner Gerald Oitzinger Raphael Klumpp Harald Vacik 《European Journal of Forest Research》2010,129(2):189-198
In Europe, the English yew species (Taxus baccata L.) is endangered. Intensive human land-use, including forest management, has caused a decrease of the yew populations all
over Europe. In Austria, gene conservation forests are used for the in situ conservation of populations of this rare tree
species by silvicultural treatments. In order to improve the conservation management in these gene conservation forests, this
study addresses the relation between competition and viability of yew populations through the use of structural diversity
indices. The structural indices, which include mingling, tree–tree distance, diameter, and tree height differentiation, were
determined for a structural group of four trees as well as the neighbouring trees of the male and female yews at the monitoring
plots on a regular grid in three gene conservation forests. Although the three study sites provided quite different environmental
conditions for English yew, the vitality of each individual yew was influenced by the inter-specific competition of the neighbouring
tree species at all sites. Low vitality was associated with a small mean distance to neighbours and large tree height differentiation.
In conclusion, we suggest that a combination of different structural indicators is needed for an integrative assessment of
conservation status in the gene conservation forests. This would help improve the evaluation of the impact management has
on yew population viability. 相似文献
15.
Rüdiger Otto Eduardo García-del-Rey Pascual Gil Muñoz José María Fernández-Palacios 《European Journal of Forest Research》2010,129(4):499-508
The Canarian pine (Pinus canariensis) exhibits a striking combination of high adult resistance to fire and intermediate serotiny. Hence, the study of its post-fire
regeneration can support valuable new insights about functional adaptations to fire. Here, we analyse the first-year seedling
establishment after fire in a P. canariensis forest on the northern slope of Tenerife, Canary Islands. The effects of fire severity and other explanatory variables on
the seedling density recorded 9 months after fire were examined. We detected a clear unimodal relationship between seedling
density and fire severity, with maximum regeneration associated with intermediate fire severity and no regeneration associated
with very high crown damage. The results suggested that high severity fires may have caused the partial destruction of the
aerial seed bank and/or the creation of unfavourable seedbed conditions for germination and seedling emergence. The density
of large pine trees, reflecting seed availability, was the second most important factor explaining the distribution of seedlings.
Cover of scorched needle litter on the ground correlated strongly and positively with pine seedling density and negatively
with fire severity. The complete lack of regeneration at sites most strongly affected by fire does not represent a major threat
for the stand recovery of the Canarian pine, due to the very high tree resistance to fire and the tremendous capacity of the
Canarian pine to resprout after fire. The observed very high seedling densities at sites with intermediate fire impacts can
probably be related to both the complete liberation of the seed bank (including seeds stored in serotinous cones) and favourable
micro-environmental conditions for seed germination and seedling establishment. 相似文献
16.
Moses Imo 《Agroforestry Systems》2009,76(2):265-273
Lack of empirical data on the effects of the taungya system on establishment and early growth of softwood plantations have partly contributed to controversial decisions regarding
the continued suitability of the system for plantation establishment in Kenya. This study examined effectiveness of taungya systems of forest plantation establishment using Cupressus lusitanica and Pinus patula trees with Zea mays (maize) as a test intercrop on two contrasting site types (deep and shallow soils) in Mt. Elgon forest, western Kenya . Four
treatments were evaluated in each site: trees with or without weed control, trees intercropped with maize, and sole maize.
Results showed that tree survival, growth and nutrient uptake, and maize growth and yield were higher in the deep soil site
than the shallow site. The t
aungya system improved tree survival and growth, effects being greater in the deep than the shallow soil site. Both Cupressus lusitanica and Pinus patula trees had the same effects on maize growth and yield, reducing maize growth by 41–48% in the deep soil sites, and by 16–26%
in the shallow site. Vector nutrient analysis and vector competition analysis of the treatment effects on growth and nutrient
uptake of the trees and the maize crop suggested competition for N on the deep soils, but competition for K and P on the shallow
soils. The study has demonstrated the applicability of graphical vector competition analysis in diagnosing tree–crop interactions
in agroforestry. 相似文献
17.
Farzam Tavankar Angela Lo Monaco Rodolfo Picchio Rachele Venanzi Mehrdad Nikooy 《European Journal of Forest Research》2018,137(1):45-55
Lime-trees (Tilia begonifolia Stev.) have countless ecological and economical values in the northern forests of Iran. Bole wounds on residual trees are commonly caused by logging. The healing ability of bole wounds and the effect of bole wounds on diameter growth in lime-trees were assessed in a natural mixed uneven-age stand. The susceptibility to decay in relation to the wound severity was also evaluated. Condition and location of lime-trees before and after selective logging were determined through systematic plot sampling. The position of each lime-tree was identified on a topographical map using the global positioning system. After 10 years from wound occurrence, tree and wound characteristics were also re-measured. Overall, 68 stems (9.7 stem ha?1) of lime-trees were found in the sampled area, 25 stems (36.8%) were damaged in the form of bole wound, and 43 stems (63.2%) were undamaged. Statistical differences between wounded or non-wounded lime-trees in terms of diameter and height were not found. Most of the wounds occurred at the height of < 1 m; the average wound size was 370.5 cm2. Wound severity was related to wound size and wound position. Wound width healing rate was 6.2 mm year?1. The wound shape was found to be a healing factor as the healing rate by width was higher than that by length. Healed wounds were only 12, 60% of bole wounds resulted in decay. Diameter growth of wounded trees was 43.5% lower than undamaged trees. The average annual diameter growth decreased by increasing wound severity. The results indicated the lime-tree is a very sensitive species to damage caused by logging (bole wound). Single-tree selection cutting needs more careful logging operations to reduce damage on residual lime-trees in order to safeguard this species, valuable in ecologic and economic terms. 相似文献
18.
Marcus Hardie Daniel Mendham Ross Corkrey Eko Hardiyanto Alen Maydra Sabar Siregar Rianto Marolop Alun Wibowo 《New Forests》2018,49(1):87-104
Indonesia’s pulp and paper industry needs a large area of sustainably grown plantations to support its continued development. Acacia mangium has been the key species underpinning the pulp and paper industries in Sumatra, however increased disease pressure on A. mangium is expected to require large-scale conversion of Acacia plantations to Eucalyptus in the near future. The effect of such a large scale change in plantation species on soil moisture, for both tree production, and catchment hydrology is unknown. In this study we sought to characterize the impacts of plantation species (Acacia or Eucalyptus) and nitrogen management, on soil moisture, soil water depletion and depth to groundwater under stands of Acacia mangium and Eucalyptus pellita over the first 2–3 years after establishment. The study was conducted in experiments at four sites in Sumatra, Indonesia. Soil moisture and soil water depletion were not influenced by plantation species or fertilizer treatment. Soil moisture content and soil water depletion were strongly influenced by shallow groundwater at two of the four sites, however depth to groundwater did not influence stem growth. Results from the field trials cautiously suggest that large scale conversion of Acacia mangium to Eucalypt species in these regions is unlikely to result in increased moisture stress, nor is conversion of plantation species likely to lead to substantial differences in catchment hydrology. This study demonstrated the importance of conducting multi-site studies when investigating biophysical relationships in forest/plantation systems. 相似文献
19.
Agroforestry is a leading alternative for food security and forest conservation. A full understanding of positive and negative,
i.e. allelopathic, interactions between crops and forest trees is necessary for producing crops and conserving forests especially
within the threatened Mediterranean forest ecosystems. The present study explored the allelopathic effects of green and senescent
leaf and soil extracts of two agroforestry trees—Pinus halepensis and Quercus coccifera—on the germination of wheat, barley, lentil, chickpea, and fababean as the major grain crops of Jordan. Results revealed
that allelopathic effects reduced seed germination of these crops. Germination reduction reached a maximum of 75% in fababean
treated with green extracts of Q. coccifera and differed among crops and extract sources, but not between tree species. Comparing between green and senescent leaf and
soil extract, regarding their effect on germination percentage, it was noticed that these effects were similar in some crops
and were different in others. Germination responses were generally different between cereals and legumes where cereals tend
to be less affected by allelopathic influences than legumes, especially fababean. We suggest using cereals such as wheat and
barley in agroforestry practices in the Mediterranean region of Jordan. 相似文献
20.
In deciduous forests, tree seeds and seedlings are frequently exposed to high predation by small rodents, and this predation
can have an important effect on forest regeneration. However, damage to large trees by small rodents has not been studied,
except for damage observed during timber production. To determine factors affecting damage to large trees by the grey red-backed
vole (Myodes rufocanus bedfordiae), the characteristics and spatial patterns of tree damage by voles at vole wintering sites were examined over 3 years in
a deciduous forest in Hokkaido. This study found that the location of damaged trees was related to vole wintering sites. Vole
damage was affected by tree species. Damaged trees were heavily concentrated in small areas. Leaning trees and trees that
had suffered previous damage were more likely to be damaged. However, the diameter at breast height was not significantly
related to vole damage. These differences in susceptibility to vole damage may result in different tree mortality. 相似文献