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Secondary tropical forests are at the forefront of deforestation pressures. They store large amounts of carbon, which, if compensated for to avoid net emissions associated with conversion to non-forest uses, may help advance tropical forest conservation. We measured above- and below-ground carbon stocks down to 1 m soil depth across a secondary forest and in oil palm plantations in Malaysia. We calculated net carbon losses when converting secondary forests to oil palm plantations and estimated payments to avoid net emissions arising from land conversion to a 22-year oil palm rotation, based on land opportunity costs per hectare. We explored how estimates would vary between forests by also extracting carbon stock data for primary forest from the literature. When tree and soil carbon was accounted for, payments of US$18–51 tCO 2 –1 for secondary forests and US$14–40 tCO 2 –1 for primary forest would equal opportunity costs associated with oil palm plantations per hectare. If detailed assessments of soil carbon were not accounted for, payments to offset opportunity costs would need to be considerably higher for secondary forests (US$28–80 tCO 2 –1 ). These results show that assessment of carbon stocks down to 1 m soil depth in tropical forests can substantially influence the estimated value of avoided-emission payments.

The stewardship of forests across multiple human generations has potential to lead to cultural innovations fostering sustainable uses. Nevertheless, positive culture–nature interactions are often disrupted due to colonial exploitation and a lack of intrinsic value ascribed to nature in capitalist economies. There is global recognition that restoring degraded ecosystems is critical to promote the welfare of people and nature by reducing the negative impacts of global climate change and diminishing biodiversity. However, with a focus on technical remedies, restoration and reforestation efforts generally fail to address the root causes of ecosystem degradation. In this perspective paper, we call for explicit incorporation of cultural values into global reforestation efforts. We focus on music as a cultural ecosystem service as music has been a prominent part of human history with clear sociological and psychological attributes that may invite mass interest and participation. We illustrate the value of musical linkages via three case studies from Europe, Africa and Hawaii focusing on native tree species, their wood, musical ecology and their interaction with culture. We show that multi‐generational stewardship of native ecosystems in Europe has allowed the refinement of the violin to its current form, one that is culturally significant for millions of people and has created a multi‐million dollar industry. This development stems from a 500‐year tradition of craftsmanship handed down across generations and illustrates that ecocultural interactions can be a strong dynamo for development of unique commodities. In contrast, in regions where extirpation of native plant species was used as a deliberate colonization strategy, many ecocultural linkages face risk of extinction. Our case studies from Africa and Hawaii illustrate how native tree species of particular value for musical expression were nearly lost and along with loss of music, important cultural connections to nature. In the context of restoration, there is also evidence that music‐based linkages can revitalize nature–culture interactions and promote restoration of native ecosystems. Incorporating native trees in global reforestation efforts is critical for ensuring that reforestation efforts capture the synergies needed for developing new ideologies that promote the well‐being of co‐dependent humans and all life. A free Plain Language Summary can be found within the Supporting Information of this article.

Tropical wetlands are some of the most threatened ecosystems in the world. Pterocarpus officinalis exists in swampy wetlands in riparian and fresh‐water coastal areas across the neotropics, supporting biodiversity and storm surge and flooding protection as well as water filtration. In Puerto Rico, P. officinalis‐dominated forests have been severely declining in recent decades, mainly due to land development. Reversing this trend in the face of climate change and projected sea level rise via ecological restoration may benefit from understanding phenotypic traits suitable for future climates. Currently, there are no seed sourcing guidelines for restoration, due to the understudied nature of the species. The goals of our study were to examine population structure and the genomic basis of variation in structural and physiological foliar traits. Seeds were collected from twelve seed sources spanning the natural distribution of P. officinalis in Puerto Rico. Water use efficiency related foliar traits were measured in well‐watered conditions from seedlings grown in a nursery experiment. A total of 109 seedlings were whole‐genome resequenced from 12 seed sources. Our results indicate strong foliar trait variation despite very little genetic differentiation among seed sources within the island, suggesting a relatively small number of genes might be involved in water‐use efficiency traits. Eleven out of thirteen foliar traits varied significantly across seed sources. Trait variation was associated with either longitude, elevation, mean annual precipitation, or isothermality. Seedlings across seed sources were observed to have different strategies for managing water use. Candidate loci identified using Genome‐Wide Association Studies were associated with signal transduction, transcription regulation, DNA and RNA methylation, transport, and primary and secondary metabolism. Restoration of this species is key in maintaining ecosystem services. Our study identified seed sources that may be successful in drier restoration conditions and match future arid climates.

A central issue in the field of community genetics is the expectation that trait variation among genotypes play a defining role in structuring associated species and in forming community phenotypes. Quantifying the existence of such community phenotypes in two common garden environments also has important consequences for our understanding of gene-by-environment interactions at the community level. The existence of community phenotypes has not been evaluated in the crowns of boreal forest trees. In this study we address the influence of tree genetics on needle chemistry and genetic x environment interactions on two gall-inducing adelgid aphids (Adelges spp. and Sacchiphantes spp.) that share the same elongating bud/shoot niche. We examine the hypothesis that the canopies of different genotypes of Norway spruce (Picea abies L.) support different community phenotypes. Three patterns emerged. First, the two gallers show clear differences in their response to host genetics and environment. Whereas genetics significantly affected the abundance of Adelges spp. galls, Sacchiphantes spp. was predominately affected by the environment suggesting that the genetic influence is stronger in Adelges spp. Second, the among family variation in genetically controlled resistance was large, i.e. fullsib families differed as much as 10 fold in susceptibility towards Adelges spp. (0.57 to 6.2 galls/branch). Also, the distribution of chemical profiles was continuous, showing both overlap as well as examples of significant differences among fullsib families. Third, despite the predicted effects of host chemistry on galls, principal component analyses using 31 different phenolic substances showed only limited association with galls and a similarity test showed that trees with similar phenolic chemical characteristics, did not host more similar communities of gallers. Nonetheless, the large genetic variation in trait expression and clear differences in how community members respond to host genetics supports our hypothesis that the canopies of Norway spruce differ in their community phenotypes.

Genetic enhancement of tree species is integral to global forest management practices with mass propagation of enhanced plant material being used to reforest whole landscapes. It is unclear, however, how genetic enhancement of basic traits such as tree growth may influence the function of life supporting soil ecosystems. We studied the potential cascading effects of genetic increases in growth of Norway spruce (Picea abies) on a range of soil chemical and biological properties. Because this species is a prime candidate for the genetic enhancement of boreal forest landscapes and it has been introduced around the world, its impacts on soil microbiomes are likely of importance both locally and globally. In a 40‐year common garden, we assessed how genetic increases in growth generated through controlled crossing of high‐quality “plus” trees from across the central boreal zone of Sweden influenced a range of soil properties beneath the canopies. Properties included pH, carbon, nitrogen, nitrate, ammonium, phosphate, respiration rate, and the composition of microbial communities assessed via phospholipid fatty acids (PLFAs). We found that Norway spruce family significantly affected each of the seven chemical properties assessed, with differences of up to 140% among families, and that three of the seven were significantly correlated with mean family growth rate. We also found that fungal PLFAs varied significantly across Norway spruce families, but these differences were not strongly related to mean family growth rate. This study, representing just one cycle of selective breeding, suggests that genetic increases in tree growth rates may also be inadvertently altering soil communities and ecosystem services. Such alterations across forest landscapes may have unexpected implications for the function of forest ecosystems (i.e., nutrient cycling) as well as processes of global significance (i.e., carbon sequestration).

Aboveground competition is often argued to be the main process determining patterns of natural forest regeneration. However, the theory of multiple resource limitation suggests that seedling performance also depends on belowground competition and, thus, that their relative influence is of fundamental importance. Two approaches were used to address the relative importance of above- and below-ground competition on regeneration in a nutrient-poor pine (Pinus sylvestris) boreal forest. Firstly, seedling establishment beneath trees stem-girdled 12 years ago show that a substantial proportion of the seedlings were established within two years after girdling, which corresponds to a time when nutrient uptake by tree roots was severely reduced without disrupting water transport to the tree canopy, which consequently was maintained. The establishment during these two years also corresponds to abundances high enough for normal stand replacement. Secondly, surveys of regeneration within forest gaps showed that surrounding forests depressed seedlings, so that satisfactory growth occurred only more than 5 m from forest edges and that higher solar radiation in south facing edges was not enough to mediate these effects. We conclude that disruption of belowground competitive interactions mediates regeneration and, thus, that belowground competition has a strong limiting influence on seedling establishment in these forests.

Climate change, as well as a more intensive forestry, is expected to increase the risk of damage by pests and pathogens on trees, which can already be a severe problem in tree plantations. Recent development of biotechnology theoretically allows for resistance enhancement that could help reduce these risks but we still lack a comprehensive understanding of benefits and tradeoffs with pest resistant GM (genetically modified) trees. We synthesized the current knowledge on the effectiveness of GM forest trees with increased resistance to herbivores. There is ample evidence that induction of exogenous Bacillus thuringiensis genes reduce performance of target pests whereas upregulation of endogenous resistance traits e.g., phenolics, generates variable results. Our review identified very few studies estimating the realized benefits in tree growth of GM trees in the field. This is concerning as the realized benefit with insect resistant GM plants seems to be context-dependent and likely manifested only if herbivore pressure is sufficiently high. Future studies of secondary pest species and resistance evolution in pest to GM trees should be prioritized. But most importantly we need more long-term field tests to evaluate the benefits and risks with pest resistant GM trees.

One main aim with genetic modification (GM) of trees is to produce plants that are resistant to various types of pests. The effectiveness of GM-introduced toxins against specific pest species on trees has been shown in the laboratory. However, few attempts have been made to determine if the production of these toxins and reduced herbivory will translate into increased tree productivity. We established an experiment with two lines of potted aspens (Populus tremula×Populus tremuloides) which express Bt (Bacillus thuringiensis) toxins and the isogenic wildtype (Wt) in the lab. The goal was to explore how experimentally controlled levels of a targeted leaf beetle Phratora vitellinae (Coleoptera; Chrysomelidae) influenced leaf damage severity, leaf beetle performance and the growth of aspen. Four patterns emerged. Firstly, we found clear evidence that Bt toxins reduce leaf damage. The damage on the Bt lines was significantly lower than for the Wt line in high and low herbivory treatment, respectively. Secondly, Bt toxins had a significant negative effect on leaf beetle survival. Thirdly, the significant decrease in height of the Wt line with increasing herbivory and the relative increase in height of one of the Bt lines compared with the Wt line in the presence of herbivores suggest that this also might translate into increased biomass production of Bt trees. This realized benefit was context-dependent and is likely to be manifested only if herbivore pressure is sufficiently high. However, these herbivore induced patterns did not translate into significant affect on biomass, instead one Bt line overall produced less biomass than the Wt. Fourthly, compiled results suggest that the growth reduction in one Bt line as indicated here is likely due to events in the transformation process and that a hypothesized cost of producing Bt toxins is of subordinate significance.

1. Implementing multi-use forest management to account for both commercial and non-commercial ecosystem services is gaining increased global recognition. Despite its spatial extent, and great economic and ecological values, few studies have evaluated the boreal forest and its management to assess the potential for simultaneous delivery of a suite of ecosystem services. 2. Using data from a Swedish long-term experiment, this study explores how biodiversity of the ground vegetation and potential delivery of multiple ecosystem services (timber production, carbon [C] storage and non-timber forest products) are influenced by two common silvicultural practices (thinning, fertilization and their interaction). 3. Diversity (diversity indices and species richness) of the ground vegetation was higher in thinned than in unthinned forest, a result attributable in part to six species of lichens that only occurred in thinned forest. In addition, supply of lichens for reindeer forage was three times higher in thinned forest. Fertilization negatively affected the lingonberry shrub (Vaccinium vitis-idaea). Timber production increased with fertilization, but decreased with thinning. The potential for C storage was highest in fertilized forests, which, apart from having the highest timber production, also supported the highest standing tree biomass. 4. The silvicultural practices evaluated induced trade-offs among the ecosystem features studied as thinning increased biodiversity of the ground vegetation, production potential of wild berries and lichens, but reduced timber production and the potential for C storage. Fertilization had the opposite effect, promoting the potential for C storage at the expense of biodiversity and the ecosystem services delivered by the ground vegetation. 5. Synthesis and applications. Increased multi-use potential is a common goal for forest management in many parts of the world. Our result shows that commonly used silvicultural practices can be used to determine the multi-use output and might be applied to maintain, or even increase the multi-use potential of the boreal forest biome. Nevertheless, trade-offs among values were common, indicating that the multi-use potential will be limited at the site level. Allowing management objectives to vary across the landscape might, in such cases, be a preferable way to achieve high multi-use potential.

Genetic modifications of trees may provide many benefits, e. g. increase production, and mitigate climate change and herbivore impacts on forests. However, genetic modifications sometimes result in unintended effects on innate traits involved in plant-herbivore interactions. The importance of intentional changes in plant defence relative to unintentional changes and the natural variation among clones used in forestry has not been evaluated. By a combination of biochemical measurements and bioassays we investigated if insect feeding on GM aspens is more affected by intentional (induction Bt toxins) than of unintentional, non-target changes or clonal differences in innate plant defence. We used two hybrid wildtype clones (Populus tremula x P. tremuloides and Populus tremula x P. alba) of aspen that have been genetically modified for 1) insect resistance (two Bt lines) or 2) reduced lignin properties (two lines COMT and CAD), respectively. Our measurements of biochemical properties suggest that unintended changes by GM modifications (occurring due to events in the transformation process) in innate plant defence (phenolic compounds) were generally smaller but fundamentally different than differences seen among different wildtype clones (e. g. quantitative and qualitative, respectively). However, neither clonal differences between the two wildtype clones nor unintended changes in phytochemistry influenced consumption by the leaf beetle (Phratora vitellinae). By contrast, Bt induction had a strong direct intended effect as well as a post experiment effect on leaf beetle consumption. The latter suggested lasting reduction of beetle fitness following Bt exposure that is likely due to intestinal damage suffered by the initial Bt exposure. We conclude that Bt induction clearly have intended effects on a target species. Furthermore, the effect of unintended changes in innate plant defence traits, when they occur, are context dependent and have in comparison to Bt induction probably less pronounced effect on targeted herbivores.