Transitional forestry in New Zealand: re-evaluating the design and management of forest systems through the lens of forest purpose.

Forestry management worldwide has become increasingly effective at obtaining high timber yields from productive forests. In New Zealand, a focus on improving an increasingly successful and largely Pinus radiata plantation forestry model over the last 150 years has resulted in some of the most productive timber forests in the temperate zone. In contrast to this success, the full range of forested landscapes across New Zealand, including native forests, are impacted by an array of pressures from introduced pests, diseases, and a changing climate, presenting a collective risk of losses in biological, social and economic value. As the national government policies incentivise reforestation and afforestation, the social acceptability of some forms of newly planted forests is also being challenged. Here, we review relevant literature in the area of integrated forest landscape management to optimise forests as nature-based solutions, presenting 'transitional forestry' as a model design and management paradigm appropriate to a range of forest types, where forest purpose is placed at the heart of decision making. We use New Zealand as a case study region, describing how this purpose-led transitional forestry model can benefit a cross section of forest types, from industrialised forest plantations to dedicated conservation forests and a range of multiple-purpose forests in between. Transitional forestry is an ongoing multi-decade process of change from current 'business-as-usual' forest management to future systems of forest management, embedded across a continuum of forest types. This holistic framework incorporates elements to enhance efficiencies of timber production, improve overall forest landscape resilience, and reduce some potential negative environmental impacts of commercial plantation forestry, while allowing the ecosystem functioning of commercial and non-commercial forests to be maximised, with increased public and biodiversity conservation value. Implementation of transitional forestry addresses tensions that arise between meeting climate mitigation targets and improving biodiversity criteria through afforestation, alongside increasing demand for forest biomass feedstocks to meet the demands of near-term bioenergy and bioeconomy goals. As ambitious government international targets are set for reforestation and afforestation using both native and exotic species, there is an increasing opportunity to make such transitions via integrated thinking that optimises forest values across a continuum of forest types, while embracing the diversity of ways in which such targets can be reached.

Revaluating forest drought experiments according to future precipitation patterns, ecosystem carbon and decomposition rate responses: A meta-analysis.

Moisture availability is a strong determinant of decomposition rates in forests worldwide. Climate models suggest that many terrestrial ecosystems are at risk from future droughts, suggesting moisture limiting conditions will develop across a range of forests worldwide. The impacts of increasing drought conditions on forest carbon (C) fluxes due to shifts in organic matter decay rates may be poorly characterised due to limited experimental research. To appraise this question, we conducted a meta-analysis of forest drought experiment studies worldwide, examining spatial limits, knowledge gaps and potential biases. To identify limits to experimental knowledge, we projected the global distribution of forest drought experiments against spatially modelled estimates of (i) future precipitation change, (ii) ecosystem total above-ground C and (iii) soil C storage. Our assessment, involving 115 individual experimental study locations, found a mismatch between the distribution of forest drought experiments and regions with higher levels of future drought risk and C storage, such as Central America, Amazonia, the Atlantic Forest of Brazil, equatorial Africa and Indonesia. Decomposition rate responses in litter and soil were also relatively under-studied, with only 30 experiments specifically examining the potential experimental impacts of drought on C fluxes from soil or litter. We propose new approaches for engaging experimentally with forest drought research, utilising standardised protocols to appraise the impacts of drought on the C cycle, while targeting the most vulnerable and relevant forests.

Characterising thermal water circulation in fractured bedrock using a multidisciplinary approach: a case study of St. Gorman's Well, Ireland.

A hydrogeological conceptual model of the source, circulation pathways and temporal variation of a low-enthalpy thermal spring in a fractured limestone setting is derived from a multidisciplinary approach. St. Gorman's Well is a thermal spring in east-central Ireland with a complex and variable temperature profile (maximum of 21.8 °C). Geophysical data from a three-dimensional(3D)audio-magnetotelluric(AMT) survey are combined with time-lapse hydrogeological data and information from a previously published hydrochemical analysis to investigate the operation of this intriguing hydrothermal system. Hydrochemical analysis and time-lapse measurements suggest that the thermal waters flow within the fractured limestones of the Carboniferous Dublin Basin at all times but display variability in discharge and temperature. The 3D electrical resistivity model of the subsurface revealed two prominent structures: (1) a NW-aligned faulted contact between two limestone lithologies; and (2) a dissolutionally enhanced, N-aligned, fault of probable Cenozoic age. The intersection of these two structures, which has allowed for karstification of the limestone bedrock, has created conduits facilitating the operation of relatively deep hydrothermal circulation (likely estimated depths between 240 and 1,000 m) within the limestone succession of the Dublin Basin. The results of this study support a hypothesis that the maximum temperature and simultaneous increased discharge observed at St. Gorman's Well each winter is the result of rapid infiltration, heating and recirculation of meteoric waters within a structurally controlled hydrothermal circulation system. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10040-021-02393-1.

Un modèle conceptuel hydrogéologique de la source, des voies de circulation et de la variation temporelle d'une source thermale à faible enthalpie dans un contexte de calcaire fracturé est dérivé d'une approche multidisciplinaire. St. Gorman's Well est une source thermale du centre-est de l'Irlande avec un profil de température complexe et variable (maximum de 21.8 °C). Les données géophysiques d'un levé audio-magnétotellurique (AMT) en trois dimensions (3D) sont combinées avec des données hydrogéologiques à intervalles de temps et des informations provenant d'une analyse hydrochimique publiée précédemment pour étudier le fonctionnement de cet intrigant système hydrothermal. L'analyse hydrochimique et les mesures à différentes périodes suggèrent que les eaux thermales s'écoulent à tout moment dans les calcaires fracturés du bassin carbonifère de Dublin, mais présentent une variabilité de débit et de température. Le modèle de résistivité électrique 3D du sous-sol a révélé deux structures importantes: (1) un contact faillé orienté NW entre deux lithologies calcaires; et (2) une faille alignée au Nord, améliorée par dissolution, d'âge cénozoïque probable. L'intersection de ces deux structures, qui a permis la karstification du socle calcaire, a créé des conduits facilitant le fonctionnement d'une circulation hydrothermale relativement profonde (profondeurs estimées vraisemblablement entre 240 et 1,000 m) au sein de la succession calcaire du bassin de Dublin. Les résultats de cette étude appuient l'hypothèse selon laquelle la température maximale et l'augmentation simultanée du débit observés à St. Gorman's Well chaque hiver sont le résultat d'une infiltration, d'un réchauffement et d'une recirculation rapides des eaux météoriques dans un système de circulation hydrothermale structurellement contrôlé.

Se deriva un modelo conceptual hidrogeológico de la fuente, las vías de circulación y la variación temporal de un manantial termal de baja entalpía en un entorno de caliza fracturada a partir de un enfoque multidisciplinar. Gorman's Well es un manantial termal en el centro-este de Irlanda con un perfil de temperatura complejo y variable (máximo de 21.8 °C). Los datos geofísicos de un estudio audio-magnetotelúrico (AMT) tridimensional (3D) se combinan con los datos hidrogeológicos de un lapso de tiempo y la información de un análisis hidroquímico previamente publicado para investigar el funcionamiento de este intrigante sistema hidrotermal. El análisis hidroquímico y las mediciones a intervalos de tiempo sugieren que las aguas termales fluyen dentro de las calizas fracturadas de la cuenca carbonífera de Dublín en todo momento, pero muestran variabilidad en la descarga y la temperatura. El modelo de resistividad eléctrica tridimensional del subsuelo reveló dos estructuras prominentes: (1) un contacto de falla alineado al NW entre dos litologías calcáreas; y (2) una falla de disolución incrementada, alineada al N, de probable edad cenozoica. La intersección de estas dos estructuras, que ha permitido la karstificación del lecho rocoso calcáreo, ha creado conductos que facilitan el funcionamiento de una circulación hidrotermal relativamente profunda (probablemente a profundidades estimadas entre 240 y 1,000 m) dentro de la sucesión calcárea de la cuenca de Dublín. Los resultados de este estudio apoyan la hipótesis de que la temperatura máxima y el aumento simultáneo de la descarga observados en St. Gorman's Well cada invierno son el resultado de una rápida infiltración, calentamiento y recirculación de aguas meteóricas dentro de un sistema de circulación hidrotermal estructuralmente controlado.

Um modelo hidrogeológico conceitual da fonte, vias de circulação e variação temporal de uma fonte termal de baixa entalpia em um ambiente de calcário fraturado é derivado de uma abordagem multidisciplinar. O poço de St. Gorman é uma fonte termal no centro-leste da Irlanda com um perfil de temperatura complexo e variável (máximo de 21.8°C). Os dados geofísicos de uma pesquisa áudio-magnetotelúrica (AMT) tridimensional (3D) são combinados com dados hidrogeológicos em intervalos de tempo e informações de uma análise hidroquimica publicada anteriormente, para investigar a operação deste intrigante sistema hidrotérmico. A análise hidroquimica e as medições em intervalos de tempo sugerem que as águas termais fluem de dentro dos calcários fraturados da Bacia Carbonifera de Dublin o tempo todo, mas exibem variabilidade na descarga e na temperatura. O modelo de resistividade elétrica 3D da subsuperfície revelou duas estruturas proeminentes: (1) um contato defeituoso alinhado a NO entre duas litologias de calcário; e (2) uma falha dissolucionalmente aumentada, alinhada a N, de provável idade Cenozóica. A intersecção dessas duas estruturas, que permitiu a carstificação da rocha calcária, criou condutos que facilitam a operação de circulação hidrotérmica relativamente profunda (profundidade estimada entre 240 e 1,000 m) dentro da sucessão de calcário da Bacia Dublin. Os resultados desse estudo suportam a hipótese de que a temperatura máxima e o aumento simultâneo da descarga observada no poço de St. Gorman a cada inverno é o resultado da rápida infiltração, aquecimento e recirculação de águas meteóricas dentro de um sistema de circulação hidrotérmica estruturalmente controlado.

Ultraviolet radiation accelerates photodegradation under controlled conditions but slows the decomposition of senescent leaves from forest stands in southern Finland.

Depending on the environment, sunlight can positively or negatively affect litter decomposition, through the ensemble of direct and indirect processes constituting photodegradation. Which of these processes predominate depends on the ecosystem studied and on the spectral composition of sunlight received. To examine the relevance of photodegradation for litter decomposition in forest understoreys, we filtered ultraviolet radiation (UV) and blue light from leaves of Fagus sylvatica and Betula pendula at two different stages of senescence in both a controlled-environment experiment and outdoors in four different forest stands (Picea abies, Fagus sylvatica, Acer platanoides, Betula pendula). Controlling for leaf orientation and initial differences in leaf chlorophyll and flavonol concentrations; we measured mass loss at the end of each experiment and characterised the phenolic profile of the leaf litter following photodegradation. In most forest stands, less mass was lost from decomposing leaves that received solar UV radiation compared with those under UV-attenuating filters, while in the controlled environment UV-A radiation either slightly accelerated or had no significant effect on photodegradation, according to species identity. Only a few individual phenolic compounds were affected by our different filter treatments, but photodegradation did affect the phenolic profile. We can conclude that photodegradation has a small stand- and species-specific effect on the decomposition of surface leaf litter in forest understoreys during the winter following leaf fall in southern Finland. Photodegradation was wavelength-dependent and modulated by the canopy species filtering sunlight and likely creating different combinations of spectral composition, moisture, temperature and snowpack characteristics.

Solar UV-A radiation and blue light enhance tree leaf litter decomposition in a temperate forest.

Sunlight can accelerate the decomposition process through an ensemble of direct and indirect processes known as photodegradation. Although photodegradation is widely studied in arid environments, there have been few studies in temperate regions. This experiment investigated how exposure to solar radiation, and specifically UV-B, UV-A, and blue light, affects leaf litter decomposition under a temperate forest canopy in France. For this purpose, we employed custom-made litterbags built using filters that attenuated different regions of the solar spectrum. Litter mass loss and carbon to nitrogen (C:N) ratio of three species: European ash (Fraxinus excelsior), European beech (Fagus sylvatica) and pedunculate oak (Quercus robur), differing in their leaf traits and decomposition rate, were analysed over a period of 7-10 months. Over the entire period, the effect of treatments attenuating blue light and solar UV radiation on leaf litter decomposition was similar to that of our dark treatment, where litter lost 20-30% less mass and had a lower C:N ratio than under the full-spectrum treatment. Moreover, decomposition was affected more by the filter treatment than mesh size, which controlled access by mesofauna. The effect of filter treatment differed among the three species and appeared to depend on litter quality (and especially C:N), producing the greatest effect in recalcitrant litter (F. sylvatica). Even under the reduced irradiance found in the understorey of a temperate forest, UV radiation and blue light remain important in accelerating surface litter decomposition.

Completing the FACE of elevated CO2 research.

We appraise the present geographical extent and inherent knowledge limits, following two decades of research on elevated CO2 responses in plant communities, and ask whether such research has answered the key question in quantifying the limits of compensatory CO2 uptake in the major biomes. Our synthesis of all ecosystem-scale (between 10 m(2) and 3000 m(2) total experimental plot area) elevated CO2 (eCO2) experiments in natural ecosystems conducted worldwide since 1987 (n=151) demonstrates that the locations of these eCO2 experiments have been spatially biased, targeting primarily the temperate ecosystems of northern America and Europe. We consider the consequences, suggesting fundamentally that this limits the capacity of the research to understand how the world's major plant communities will respond to eCO2. Most notably, our synthesis shows that this research lacks understanding of impacts on tropical forests and boreal regions, which are potentially the most significant biomes for C sink and storage activity, respectively. Using a meta-analysis of the available data across all biomes, we show equivocal increases in net primary productivity (NPP) from eCO2 studies, suggesting that global validation is needed, especially in the most important biomes for C processing. Further, our meta-analysis identifies that few research programs have addressed eCO2 effects on below-ground C storage, such that at the global scale, no overall responses are discernable. Given the disparity highlighted in the distribution of eCO2 experiments globally, we suggest opportunities for newly-industrialized or developing nations to become involved in further research, particularly as these countries host some of the most important regions for tropical or sub-tropical forest systems. Modeling approaches that thus far have attempted to understand the biological response to eCO2 are constrained with respect to collective predictions, suggesting that further work is needed, which will link models to in situ eCO2 experiments, in order to understand how the world's most important regions for terrestrial C uptake and storage will respond to a future eCO2 atmosphere.

Enhanced UV-B and elevated CO(2) impacts sub-arctic shrub berry abundance, quality and seed germination.

This study investigated the effects of long-term-enhanced UV-B, and combined UV-B with elevated CO(2) on dwarf shrub berry characteristics in a sub-arctic heath community. Germination of Vaccinium myrtillus was enhanced in seeds produced at elevated UV-B, but seed numbers and berry size were unaffected. Elevated UV-B and CO(2) stimulated the abundance of V. myrtillus berries, whilst UV-B alone stimulated the berry abundance of V. vitis-idaea and Empetrum hermaphroditum. Enhanced UV-B reduced concentrations of several polyphenolics in V. myrtillus berries, whilst elevated CO(2) increased quercetin glycosides in V. myrtillus, and syringetin glycosides and anthocyanins in E. hermaphroditum berries. UV-B × CO(2) interactions were found for total anthocyanins, delphinidin-3-hexoside and peonidin-3-pentosidein in V. myrtillus berries but not E. hermaphroditum. Results suggest positive impacts of UV-B on the germination of V. myrtillus and species-specific impacts of UV-B × elevated CO(2) on berry abundance and quality. The findings have relevance and implications for human and animal consumers plus seed dispersal and seedling establishment.

Long-term nitrogen additions increase likelihood of climate stress and affect recovery from wildfire in a lowland heath.

Increases in the emissions and associated atmospheric deposition of nitrogen (N) have the potential to cause significant changes to the structure and function of N-limited ecosystems. Here, we present the results of a long-term (13 year) experiment assessing the impacts of N addition (30 kg ha(-1)  yr(-1) ) on a UK lowland heathland under a wide range of environmental conditions, including the occurrence of prolonged natural drought episodes and a severe summer fire. Our findings indicate that elevated N deposition results in large, persistent effects on Calluna growth, phenology and chemistry, severe suppression of understorey lichen flora and changes in soil biogeochemistry. Growing season rainfall was found to be a strong driver of inter-annual variation in Calluna growth and, although interactions between N and rainfall for shoot growth were not significant until the later phase of the experiment, N addition exacerbated the extent of drought injury to Calluna shoots following naturally occurring droughts in 2003 and 2009. Following a severe wildfire at the experimental site in 2006, heathland regeneration dynamics were significantly affected by N, with a greater abundance of pioneering moss species and suppression of the lichen flora in plots receiving N additions. Significant interactions between climate and N were also apparent post fire, with the characteristic stimulation in Calluna growth in +N plots suppressed during dry years. Carbon (C) and N budgets demonstrate large increases in both above- and below-ground stocks of these elements in N-treated plots prior to the fire, despite higher levels of soil microbial activity and organic matter turnover. Although much of the organic material was removed during the fire, pre-existing treatment differences were still evident following the burn. Post fire accumulation of below-ground C and N stocks was increased rapidly in N-treated plots, highlighting the role of N deposition in ecosystem C sequestration.

A computationally inspired investigation of the solid forms of (R)-1-phenylethylammonium-(S)-2-phenylbutyrate.

Following the computation of a lattice energy landscape which predicted that there should be more stable, denser forms of (R)-1-phenylethylammonium-(S)-2-phenylbutyrate, crystallizations from a range of solvents were performed to search for other polymorphs and investigate the possibility that the known P4(1) structure could be a hydrate. Extensive crystallization experiments from a wide range of solvents gave fine needles or microcrystalline samples. A redetermination of the P4(1) structure by powder X-ray diffraction located all protons, and in conjunction with other experimental and computational evidence showed that the structure was anhydrous. Evidence for two additional forms was found as mixtures with form I. These include an orthorhombic form, possibly a Z' = 3 polymorph, and another as yet unidentified form obtained as a minor component from dichloromethane solution. However, both these forms appear to be metastable with respect to form I (P4(1)), which is therefore probably the most thermodynamically stable form that can be crystallized from solution under ambient conditions. This determination of the solid state behavior of the less readily crystallized member of the diastereomeric salt system (R)-1-phenylethylammonium-(R/S)-2-phenylbutyrate provides a challenge to the theoretical modeling to explain its ideal resolution behavior.