Achieving cost‐effective landscape‐scale forest restoration through targeted natural regeneration

Applied nucleation, mostly based upon planting tree islands, has been proposed as a cost‐effective strategy to meet ambitious global forest and landscape restoration targets. We review results from a 15‐year study, replicated at 15 sites in southern Costa Rica, that compares applied nucleation to natural regeneration and mixed‐species tree plantations as strategies to restore tropical forest. We have collected data on planted tree survival and growth, woody vegetation recruitment and structure, seed rain, litterfall, epiphytes, birds, bats and leaf litter arthropods. Our results indicate that applied nucleation and plantation restoration strategies are similarly effective in enhancing the recovery of most floral and faunal groups, vegetation structure and ecosystem functions, as compared to natural regeneration. Seed dispersal and woody recruitment are higher in applied nucleation and plantation than natural regeneration treatments; canopy cover has increased substantially in both natural regeneration and applied nucleation treatments; and mortality of planted N‐fixing tree species has increased in recent years. These trends have led to rapid changes in vegetation composition and structure and nutrient cycling. The applied nucleation strategy is cheaper than mixed‐species tree plantations, but there may be social obstacles to implementing this technique in agricultural landscapes, such as perceptions that the land is not being used productively. Applied nucleation is likely to be most effective in cases where: planted vegetation nuclei enhance seed dispersal and seedling establishment of other species; the spread of nuclei is not strongly inhibited by abiotic or biotic factors; and the approach is compatible with restoration goals and landowner preferences. Synthesis and applications. Results from our 15‐year, multi‐site study show that applied nucleation can be a cost‐effective strategy for facilitating tropical forest regeneration that holds promise for helping to meet large‐scale international forest restoration commitments.

Monitoring secondary forest regrowth is a priority in forest restoration strategies. A site history helps in understanding the present status of natural regeneration in the three landscapes impacted by bauxite mining. Nonetheless, high rainfall in bauxite residue storage areas can facilitate natural regeneration of forest. This research analyzed the natural regeneration of forest after thirty years of different land use histories at three bauxite mining areas of the Upper Demerara—Berbice region of Guyana. There are no man made forest plantations in the three landscapes being reviewed. The methodology included: 1) the selection of three sampling landscapes with different land use histories 2) the generation Land Use/Land Cover maps using KMeans unsupervised classification of satellite images in each landscape and 3) the assessment of landscape structure of the land cover classes for year 2020 at class and landscape level using landscape metrics. The assessment of landscape structure of the land cover classes was carried-out with landscape metrics for the comparisons at class and landscape level. Principal component analysis enables the identification of main patterns among landscape-level metrics and land cover classes. Discriminant classification of the landscape classes was analyzed with the different metrics. The results suggest that Normalized Difference Vegetation Index and KMeans unsupervised classification can be used to evaluate the difference in natural forest regeneration among landscapes with differing land use histories. The landscape metrics revealed secondary stages of forest succession. The Landscape Shape Index and Edge Density were the most significant for landscape differentiation. The result of the various land uses reveals a mosaic of early, intermediate, and late successional sequences.

During recent decades, forests have expanded into new areas throughout the whole of Norway. The processes explained as causing the forest expansion have focused mainly on climate or land use changes. To enable a spatially explicit separation of the effects following these two main drivers behind forest expansion, the authors set out to model the potential for natural forest regeneration following land use abandonment, given the present climatic conditions. The present forest distribution, a number of high-resolution land cover maps, and GIS methods were used to model the potential for natural forest regeneration. Furthermore, the results were tested with independent local models, explanatory variables and predictive modelling. The modelling results show that land use abandonment, in a long-term perspective, has the climatic and edaphic potential to cause natural forest regeneration of 48,800 km2, or 15.9% of mainland Norway. The future natural forest regeneration following land use change or abandonment can now be spatially separated from the effects of climate changes. The different independent model tests support the main findings, but small fractions of the modelled potential natural forest regeneration will probably be caused by other processes than land use abandonment.

Tree plantations are sometimes the only alternative in restoring forest landscapes, at least in the short term, especially on very badly degraded soils. Low soil fertility, soil compaction after abandonment from cattle grazing, and invasion by grasses and other aggressive vegetation can be serious obstacles to natural forest regeneration. As the area of degraded lands expands, there is a greater need for tree species that can grow in such conditions and yield useful products (timber, fuelwood, and others) as well as environmental benefits (recovery of ecosystem biodiversity, soil conservation, watershed protection, carbon sequestration). Tree species chosen for a plantation in the context of forest restoration can provide benefits from the tree products (timber, fuelwood, leaf mulches, etc.), and from their ecological effects, for example, nutrient recycling, or attracting birds and other wildlife to the landscape. The choice of a tree species depends on whether both productive and ecological advantages can be achieved in the same system, and in some cases one function, either productive or environmental, may be desired. Within a forest landscape, the preferred choice for restoration would be natural regeneration. Planting would only be a secondary option, to be used in cases where natural regeneration cannot proceed due to the obstacles mentioned above (poor soil conditions, long distances to seed sources, isolation, invasion by aggressive grasses). Within a landscape context, there should be a balance of socioeconomic goals (e.g., productivity) and biodiversity objectives for restoration. The following factors influence species’ choice for plantations: 38 Selecting Tree Species for Plantation

Natural forest regeneration is gaining more and more importance in European forestry. The more widespread use of natural regeneration allows the formation of multifunctional and durable forests. Much attention was paid to the cultivation of pine stands, with particular emphasis on obtaining seedlings. However, few publications synthetically describe the care treatments in pine crops and young forests from self-seeding forest regeneration. Considering the importance of Scots pine in Polish forestry, it is justified to present the methods and ways of nurturing pine stands that come from the natural regeneration of this species. In the second or third year after initiating the natural regeneration of Scots pine on the clearing plot, a schematic thinning of the future cultivation is performed. For this purpose, the inter-row harrowing treatment on future cultivation is used with the Lowland disc harrow. In the last season, early cleaning is performed before the crop is closed. In the early stages of the development of pine seedlings, one cannot forget about the strong competition from herbaceous vegetation. Late cleaning, in the case of managing the crops of natural origin in the unit, is performed in two turns. Early thinning in this type of stand is usually carried out after 20 years of stand growth. The goals of maintenance pruning do not differ from those adopted as standard for planted stands. It should be clearly emphasized that when managing pine stands of natural origin in the Skwierzyna Forest District, the priority is to achieve breeding goals. The condition and quality of cultivated crops and young forests are always a priority for the owners of the local forests, regardless of the economic situation in the timber market or the demand for a given raw material in a given period.

The Atlantic Forest suffered five centuries of continuous deforestation related to successive economic cycles, and is now reduced to 11.7 % of its original cover. The Atlantic Forest Restoration Pact was launched in 2009 and aims to restore 15 million hectares until 2050. Natural regeneration can play an important role in meeting this target, however little attention has been paid to this process and there is a gap in the knowledge about its driving factors at the landscape scale. We mapped forest cover of an Atlantic Forest municipality in Southeastern Brazil, in five timeslots between years 1978 and 2014, and used the weights of evidence method for modeling its spatial dynamics, in order to understand where natural regeneration is occurring and which are the main factors related to this phenomenon. In 36 years, forest cover increased 3,020 hectares (15.3 %), related to the decreasing of both rural population (R2 = 0.9794, p = 0.0013) and cropland cover (R2 = 0.8679, p = 0.0212). Landscape metrics shows the increment of number of fragments and structural connectivity among them. The main spatial variables influencing forest cover dynamics were topographic position, slope, solar radiation, soil type and distance to forest, urban areas and roads. Secondary forests provide ecosystem services that can turn into economic benefits, and natural regeneration can reduce restoration costs to the municipality. The cost of active restoration of the same area would have meant a total expense of U$ 15.1 million (U$ 419 k/year). We show here that spontaneous regeneration must be accounted for and incorporated into the spatial planning of Atlantic Forest restoration.

The effectiveness of forests therapeutic impact is based on its species’ and age structure, silvicultural features, biological productivity, regenerative ability, forest management intensity and its methods. The processes of natural regeneration of a forest stand and its growth are the main factors of the forest’s ecosystem proper functioning and a disruption in these processes can lead to a transformation of the whole biocenosis, a change of a typological community. Technogenic pollution is a huge stress factor for trees, and its impact is especially evident in regions with a high concentration of industrial facilities, namely, in Moscow city. One of the most serious consequences of technogenic pollution is the deterioration of long-established forests, which subsequently may reduce its ability to adapt to ever-changing environmental conditions and its protective functions. The article discusses issues regarding the natural regeneration of forests on urbanized territories of Moscow on the example of the Forest experimental station of the Russian State Agrarian University - Moscow Timiryazev Agricultural Academy. The natural regeneration of tree species is one of the most relevant issues of forest and park management. The aim of this project is to estimate natural regeneration in mixed forest stands of urbanized areas, to provide recommendations on the organization of forest regeneration measures in urban environments. The article provides methods and results of field research and recommendations on reforestation measures under these conditions. The research of the cenobiotic connections and the undergrowth of different species with key elements of grass cover in its habitat, will allow a more positive dynamics in the use of natural resources, which will contribute to preservation and restoration of forests.

Summary 1. Birds inhabiting farmland are of conservation concern around the world. In Australia, conservation management has focused primarily on woodland environments. By contrast, semi-natural open areas have received less attention. We argue that long-term conservation strategies should consider broad gradients of environmental conditions. Otherwise, there is a risk that semi-natural open areas will degrade through ‘benign neglect’, and currently common species using these areas will become uncommon. 2. We examined how birds responded to three environmental gradients in an Australian livestock grazing landscape: tree density, grazing intensity and nutrient enrichment. First, we investigated changes in species composition across the environmental gradients in multivariate space. Secondly, we modelled species richness and the response of selected individual species in relation to the gradients. Thirdly, we examined if there were patterns in guild composition and body mass distribution. 3. Tree density was the primary driver of virtually all patterns observed. Species richness peaked at moderately high tree densities. With increasing tree density, species composition changed, foraging guild composition changed and the median body mass of bird species decreased. Small insectivores were more likely to occur in areas with high tree densities, whereas large granivores were more likely to occur in areas with relatively low tree densities. Grazing intensity and nutrient enrichment were less strongly related to bird distribution patterns, although the indirect effects of these gradients may be substantial because they affect tree regeneration. 4. sSynthesis and applications. Relatively dense woodland patches were important for species already of conservation concern, lending support to their active conservation management, for example through livestock exclusion. However, semi-natural open areas also were used by many birds, which represented a different mix of body sizes and foraging guilds. Scattered trees occurring at a range of densities are key habitat elements in semi-natural open areas. However, many scattered trees are dying and are not being replaced by natural regeneration or tree planting. If areas with scattered trees continue to degrade, there is a risk that currently common farmland birds will decline. Management strategies aiming to maintain scattered trees therefore are important, including the planting of individual trees and the adoption of grazing practices that allow for natural tree regeneration.

The objective of the study reported here was to compare voivodships in terms of forest area, forest regeneration area, afforested area, thinned forest area and natural forest regeneration area Main Statistical Office data for Polish voivodships was analysed. It included forest area, natural forest regeneration and silviculture activities (forest regeneration, afforestations and thinning) in all forests, state-owned forests and privately-owned forests. Voivodships were compared using the arithmetic mean, the indicator of structure, the average rate of change, principal component analysis and cluster analysis. Principal Component Analysis, revealed that state-owned forest area, forest regeneration in state forests, total forest regeneration, and thinning in state-owned forests had the greatest share in the multivariate variation among voivodships analysed in terms of forestry. Cluster analysis yielded two groups of voivodships. The voivodships in the first group had a higher average total forest area, area of state-owned forests, total area of forest regeneration and forest regeneration in state-owned forests, area of natural forest regeneration and thinning in state-owned forests. On average, forests of voivodships which formed group 2 included less privately-owned forests in which fewer forest regeneration and afforestation activities had been conducted. Opolskie and Śląskie Voivodships as well as Łódzkie and Świętokrzyskie Voivodships were the most similar in terms of all the analysed characteristics.

Abandoned pastures are increasingly targeted for forest restoration in the neotropics. However, the dominance of such areas by fodder grasses imposes a challenge for efficient and low cost control. Therefore, we questioned whether alien and native grasses equally affect: (1) natural regeneration; (2) natural regeneration under artificial perches; and (3) planted seedling development. Our study was carried out in an abandoned pasture in southeastern Brazil, in the Atlantic Forest biome. For (1) we installed plots in grass patches of Melinis minutiflora (molasse grass, an alien grass) and Imperata brasiliensis (satintail, a native grass that occurs in degraded areas); for (2) we installed plots under perches in alien and native grass patches; and for (3) we compared overall planted seedling mortality and development of four tree species in alien and native grass patches. Density and diversity of woody species in natural regeneration and under perches were similar for invasive and native grass patches. However, species composition differed between alien and native grass patches (Ellenberg similarity of 28% for perches and 35% for natural regeneration in different grass patches). Seedling mortality was similar for both alien and native grasses. Except for two tree species, development was similar for both native and alien grass patches. Our results indicate that the biological barriers imposed by a given grass species for forest succession and restoration must not be estimated based only on the species' origin.

Micro-environmental factors viz., soil moisture and light intensity are important factors that affect natural regeneration in forests. These factors vary spatially depending on the overhead canopy density of the forest. The present study focused on studying the effect of variation of soil moisture and light intensity on natural regeneration of sal species (Shorea robusta) under different micro-environments due to overhead canopy of varying forest density. Experimental plots of 40m× 40m size were laid under different overhead canopy densities in a small sal forested watershed in the foot hills of Himalayas in Nainital District of Uttarakhand State, India. The plots were monitored on a long term basis for soil moisture at multi depths, light intensity and natural regeneration of sal. The results of the study revealed that the natural regeneration was highest under C1 (up to-0.30) canopy followed by C2 (0.30–0.50), and C3 (0.50–0.70) canopies. The C3 canopy showed the dying back of sal shoots over 4 years of study. The highest R2 value of linear regression between incremental score of plot regeneration and average soil moisture content was obtained as 0.156 for average soil moisture content during non-monsoon months at 100 cm depth. The R2 value between incremental score of plot regeneration and annual average light intensity was obtained as 0.688 which indicated that the regeneration is largely dependent on the light intensity conditions during the year. The multiple linear regression analysis between the incremental score of regeneration and the average light intensity and average soil moisture content revealed that that about 80% of variation in regeneration is explained by both the factors.

Natural regeneration occupies an important position in forest ecosystems and is affected by various factors. Exploring natural regeneration and its influencing factors is helpful to understand the forest community dynamic. Evergreen broad-leaved forest is an essential zonal vegetation type in China. However, the natural regeneration of evergreen broad-leaved forests in the northernmost margin of subtropical zone has not been reported. Here we investigated 22 observed variables, and selected four categories of latent variables stand factor, topographical factor, soil factor and tree diversity as influential factors based on the survey data of 50 (20 m × 20 m) permanent sample plots. The structural equation model was introduced to distinguish the direct, indirect and total effect of influencing factors on understory woody plant regeneration diversity and regeneration density, respectively. We found 51 regeneration species under 31 families and five dominant species Loropetalum chinense, Symplocos sumuntia, Quercus glauca, Ilex chinensis, and Eurya japonica in the study area. Soil factor was the primary control of regeneration, which had the greatest and negative total effect on regeneration diversity (-0.436) and regeneration density (-0.298). The main soil factors that affected regeneration diversity and regeneration density were total phosphorus and soil organic matter, respectively. Soil factor mainly affected indirectly regeneration by mediating through its impacts on tree diversity. Tree diversity and topographical factor all were significantly positively correlated with the regeneration diversity and regeneration density. Stand factor had a significantly negative correlation with regeneration density but a significantly positive with regeneration diversity. Our study provides the basis to introduce appropriate artificial auxiliary measures for improving the natural regeneration of forest stands, so as to promote sustainable forest management.

For the maintenance and conservation of riparian areas it is necessary to know the layer’s of the forest, like the natural regeneration of. According to that, the porpoise of this paper is to characterize the natural regeneration of a riparian forest in the city of Jaguari, central region in Rio Grande do Sul, by describing the diversity, structural parameters of natural regeneration, dispersion syndromes and ecological groups. For the sampling were plottedsystematically 15 samples with size 5 x 10 m. Inside the plots were identified and measured the trees with height (h) equal or greater than 1.5 m, and diameter at breast height (DBH) less than 10 cm. Were sampled 546 individuals from 16 families and 26 species. The family Myrtaceae presented the highest number of species (6 species) and the greatest percentage of trees (54.8%). The Shannon’s index was equal to 2.21 nats.ind-1 and Pielou’s index was equal to 0.68, indicating low diversity and an uniform distribution among the species. Eugenia uniflora L. was the most characteristic species of natural regeneration. We observed that there is a deficit of small-sized individuals (0,3 ? DAP < 1,3 cm; 1,5 ? h < 2,5 m). The zoochoryc syndrome was mostexpressive in natural regeneration, being the main form to spread diaspores on place. Most species were classified as initial secondary (50%) or pioneer (26.9%), indicating that the riparian vegetation is altered, this indicate that riparian vegetation is in phase of recuperation of antropic activities.

A spatially explicit index for mapping Forest Restoration Vocation (FRV) at the landscape scale: Application in the Rio Doce basin, Brazil

Plant diversity and tree responses following contrasting disturbances in boreal forest