Somidh Saha

Somidh Saha
Karlsruhe Institute of Technology | KIT · Institute for Technology Assessment and Systems Analysis (ITAS)

Dr. rer. nat. Forest Sciences
Head of Research Group Sylvanus at the KIT, Germany

About

56
Publications
32,036
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Introduction
We aim to investigate how the resilience of forests can be increased, and trade-offs between ecosystem services can be reduced. Therefore, we do inter-and transdisciplinary research by cross-cutting ecology, plant biology, physiology, silviculture, forest technologies, and biostatistics to socio-cultural, justice, and economics of forest management. Our research spans from greenhouse to forest, and jungle trees to city trees, in temperate and tropical regions of Europe, Asia and Africa.
Additional affiliations
January 2017 - present
Karlsruhe Institute of Technology
Position
  • Researcher
November 2013 - December 2016
University of Freiburg
Position
  • PostDoc Position
January 2013 - April 2013
Forstliche Versuchs- und Forschungsanstalt Baden-Württemberg
Position
  • Researcher
Education
October 2008 - November 2012
University of Freiburg
Field of study
  • Forestry
July 2003 - June 2005
May 2000 - June 2003
Presidency College, University of Calcutta
Field of study
  • Zoology (Honours)

Publications

Publications (56)
Article
Full-text available
http://authors.elsevier.com/a/1TjEU1L~Gw8~wT Increasing frequency of extremely dry and hot summers in some regions emphasise the need for silvicultural approaches to increase the drought tolerance of existing forests in the short term, before long-term adaptation through species changes may be possible. The aim of this meta-analysis was to assess t...
Article
Full-text available
Cultural ecosystem services (CES) of urban and peri-urban forests (UPF) contribute to the urban population's health and well-being. However, UPF face numerous threats from increasing urbanization and climate change. A comprehensive understanding of the flow of the forests' CES between urban and peri-urban areas was lacking. Further, there is little...
Article
Reducing trade-offs among ecosystem services (ES) from urban and peri-urban forests (UPF) is crucial for human wellbeing. We performed spatial analyses and quantified the supply and trade-offs between 23 ES (grouped into three categories: provisioning, regulating, and supporting) from UPF in the Karlsruhe region, southwest Germany. The supply of ES...
Article
Full-text available
Key Message In an urban area, resistance and resilience of stem diameter growth differ substantially between tree species. Traffic emissions are reflected in wood nitrogen isotopes, but do not affect drought tolerance. Abstract With increasing drought and heat, the benefits of urban trees such as shading and cooling become more important. Yet, it...
Article
Full-text available
Trees in cities provide multiple ecosystem services. However, simultaneously ensuring healthy trees with high habitat diversity can be challenging in a harsh urban environment. We compared health, microhabitats, and bat activities between native (Quercus robur L.) and non-native (Quercus rubra L.) oaks growing in different urban habitats (street vs...
Poster
Full-text available
While urban trees provide diverse values including provisioning, supporting, regulating, and cultural ecosystem services, citizens have limited knowledge about the trees and their benefits. This research aims to tackle the illiteracy of urban forestry and increase the engagement of citizens in urban forest management by providing access to instant...
Preprint
Full-text available
Increasing urbanization, climate change, and plant disease pose accumulative threats to city and community-owned forests (CCF). This requires the forest to adapt to new climatic conditions to continuously provide essential recreational functions for the urban population in the future. The COVID-19 pandemic increased the demand for CCF as a place to...
Article
Full-text available
The contribution of non timber forest products (NTFPs) has been acknowledged globally for their role in conservation, income generation, livelihood improvement and rural development. The potential of a NTFP-based bioeconomy has given a new dimension to the forest sector, and NTFPs are now considered favourably by the resource rich developing econom...
Article
Full-text available
Differences in the accessibility to urban resources between different racial and socioeconomic groups have exerted pressure on effective planning and management for sustainable city development. However, few studies have examined the multiple factors that may influence the mitigation of urban green spaces (UGS) inequity. This study reports the resu...
Article
Full-text available
Trees in cities provide multiple ecosystem services. However, simultaneously ensuring healthy trees with high habitat diversity can be challenging in a harsh urban environment. We compared health, microhabitats, and bat activities between native ( Quercus robur L.) and non-native ( Quercus rubra L.) oaks growing in different urban habitats (street...
Article
Full-text available
Converting monospecific into mixed forests can increase forests’ resilience against climate change-related extreme events such as droughts and storms. This insight is especially true when the tree species help each other, such as the fir in low mountain regions like the Black Forest, which improves the water supply of the beech through the hydrauli...
Article
Full-text available
Forests of Jammu and Kashmir (J&K) have a rich diversity of valuable non-timber forest products (NTFP) that local communities extract for their sustenance and income. The region is home to over 60% of species recognized for novel bio-medicinal properties in the Indian Himalayas. There is significant national and international demand for these speci...
Article
Full-text available
In the times of enlarging cities and more people living in cities, it is essential to maintain the quality of life for everyone. Urban forests make a significant contribution to this. In urban areas, productive ecosystems are essential to maintain human health and well-being. However, problems like increasing urbanization, changing climate, and pol...
Article
Full-text available
European beech (Fagus sylvatica L.) trees are becoming vulnerable to drought, with a warming climate. Existing studies disagree on how radial growth varies in European beech in response to droughts. We aimed to find the impact of multiple droughts on beech trees’ annual radial growth at their ecological drought limit created by soil water availabil...
Article
Full-text available
The montane subtropical broad-leaved humid forests of Meghalaya (Northeast India) are highly diverse and situated at the transition zone between the Eastern Himalayas and Indo-Burma biodiversity hotspots. In this study, we have used inventory data from seedlings to canopy level to assess the impact of both biotic and abiotic disturbances on structu...
Article
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Jede*r kann einen Beitrag zu Arten- und Klimaschutz durch Veränderungen im eigenen Garten leisten. Das ist die Idee der Kampagne, die in dem Projekt GrüneLunge konzipiert und in der Stadt Rheinstetten durchgeführt wird. Zu Beginn wurden Bürger*innen mit öffentlichen Veranstaltungen über naturnahe Gartengestaltung informiert. Im Anschluss werden 16...
Preprint
Full-text available
Abstract: The montane subtropical broadleaved humid forests of Meghalaya (Northeast India) are highly diverse and situated at the transition zone between the Eastern Himalayas and Indo-Burma biodiversity hotspots. Fagaceae family are the keystone species forms an important component of these forests. These forests in Meghalaya are highly degraded a...
Article
Full-text available
Partition of British India in 1947 triggered a huge refugee crisis in India. In addition, low agricultural yield and high population growth fueled food insecurity. The fear of the Bengal Famine of 1943 was still fresh and the Indian Government wanted to prevent further famines. The philanthropic organizations of the USA (Rockefeller and Ford Founda...
Article
Full-text available
Small-scale harvesting methods as practised in close-to-nature forestry may disadvantage the regeneration of more light-demanding tree species such as most oaks and thus cause regeneration failure. Conducted in south-western Germany, this study examined photosynthetic performance and height growth of naturally regenerated 7-year-old sessile oak (Qu...
Article
Full-text available
Understanding the structure and composition of native forests is a prerequisite in developing an adaptive forest management plan for Himalayan forest ecosystems where climate change is rapid. However, basic information on forest structure and composition are still limited in many places of the Eastern Himalayas. In this study, we aimed to understan...
Article
Full-text available
Scientific studies have shown that mixed forests of silver fir (Abies alba Mill.) and European beech (Fagus sylvatica L.) provide higher ecosystem services than monospecific forests. Mixed forests are known for their high resilience to climate change impacts and superior biodiversity compared to monospecific forests. Despite this superiority, the t...
Article
Full-text available
The Himalayan region is not only threatened by rapid changes in anthropogenic activities but also by global climate change. Given the uncertainties of magnitude and characteristics of climate change, prior knowledge of long-term changing distribution pattern of forests is of crucial importance. Owing to the heterogeneity of the Himalayan mountain s...
Preprint
Scientific studies had shown that mixed forests of silver fir (Abies alba Mill.) and European beech (Fagus sylvatica L.) provide higher ecosystem services than monospecific forests. Mixed forests are known for their high resilience to climate change impacts and superior biodiversity compared to monospecific forests. In many countries, promotion of...
Book
Full-text available
In German: Das Projekt soll quantifizieren, inwiefern die Speicherung von Kohlenstoff in der aufstockenden Biomasse von Wäldern als Mitigationsstrategie dem Ziel der Anpassung der Wälder an den Klimawandel entspricht oder diesem zuwider läuft. Konkret wird analysiert, ob eine weitere Anreicherung von Kohlenstoffvorräten in deutschen Wäldern a) die...
Article
Full-text available
Wild cherry trees produce high-quality timber and provide multiple ecosystemservices. However, planting and tending cherry stands in conventional rows are too costly.Therefore, low density group planting was trialled as an alternative to row planting. The mortality, growth, and quality of planted cherry trees were compared between the group and row...
Article
Biomass and leaf area equations are often required to assess or model forest productivity, carbon stocks and other ecosystem services. These factors are influenced by climate, age and stand structural attributes including stand density and tree species diversity or species composition. However, such covariates are rarely included in biomass and lea...
Article
Full-text available
The Himalayas are well known for high diversity and ethnobotanical uses of the region’s medicinal plants. However, not all areas of the Himalayan regions are well studied. Studies on ethnobotanical uses of plants from the Eastern Himalayas are still lacking for many tribes. Past studies have primarily focused on listing plants’ vernacular names and...
Article
Full-text available
Oaks are becoming increasingly important for future forest management as the climate in central Europe warms. Owing to the high costs of conventional row planting, artificial oak stand establishment in the form of “clusters” became popular in central Europe beginning in the 1970s. In cluster plantings, oaks are either planted in groups of ca. 20-25...
Preprint
Full-text available
The Himalaya is well known for high diversity and ethnobotanical uses of medicinal plants. However, not all areas of the Himalayas are well studied. In particular, studies on ethnobotanical uses of plants from the Eastern Himalayas are rare and lacking for many tribes. Past studies primarily focused on listing plants name and their traditional medi...
Article
Full-text available
Recent studies have reported superior tree quality and comparable tree growth of oaks planted in group compared with row planting. However, a comparative assessment of the potential future crop trees (PFCTs) between group and row planting is still lacking. Here, we compared the density and tree quality of planted oaks and other naturally regenerate...
Article
Full-text available
Biomass equations for European beech (Fagus sylvatica L.) trees growing on dry sites have not been published, although such equations are needed for a proper estimation of the biomass of beech trees growing naturally at their drought limit in dry forests. We aimed to: (1) develop new allometric above-ground biomass equations for European beech tree...
Conference Paper
Full-text available
Lecture was given by Somidh Saha which was reported by Hilary Burke in Forestry Journal.
Article
Full-text available
„Pflanzenklumpen“ (Clusterpflanzungen) werden bereits seit Längerem als Alternativen zur konventionellen Vollkultur in Reihenpflanzung erprobt. Mit der Trupppflanzung steht offensichtlich ein sehr flexibles, vorteilhaftes Verfahren zur Begründung von Eichenmischbeständen zur Verfügung. Über die Anzahl an Trupps je Hektar können anfängliche finanzie...
Article
Full-text available
• Context Cluster planting has become a conventional establishment method for oaks in central Europe, where the spacing of seedlings within clusters varies between “nests” (0.2 x 0.2 m) and “groups” (1 x 1 m). Although the space between clusters is expected to fill with voluntary regeneration, its competitive effect on oak growth and quality had no...
Article
Full-text available
Growth and survival of young European beech (Fagus sylvatica L.) is largely dependent on water availability. We quantified the influence of water stress (measured as Available Soil Water Storage Capacity or ASWSC) on vitality of young beech plants at a dry site. The study site was located in a semi-natural sessile oak (Quercus petraea (Mattuschka)...
Article
Full-text available
Low density plantings complemented by natural regeneration is an increasingly common reforestation technique to ensure growth of a sufficient number of trees from desired species while maintaining natural processes such as succession. One such form of low density planting that aims at lowering establishment costs—oak clusters—has been developed as...
Article
Full-text available
Nester-oder Trupppflanzungen bei Eiche – was ist besser? Eichennester-und Eichentrupppflanzungen (auch Clusterpflanzungen) werden seit den 1980er bzw. 1990er Jahren als ökologische und ökonomische Alternativen zur traditionellen Reihenpflanzung insbesondere nach Sturmwurf vermehrt für die Bestandesbegründung genutzt. In einer auf Erhebungen aus ein...
Article
Full-text available
In Zeiten des Klimawandels werden Mischbestände zur Risikominimierung empfohlen. Doch wie soll die Mischung in die Bestände kommen? Eine international angelegte Studie führte nun einen Vergleich zwischen den „Pflanzen-Klumpen“,auch Clusterpflanzungen genannt, und der konventionellen Vollkultur in Reihen pflanzung durch. Dabei wurden Wachstum und Qu...
Book
Full-text available
Pedunculate oak (Quercus robur) and sessile oak (Q. petraea) are likely to become increasingly important in Central Europe owing to their stability, tolerance of relatively warm climates, and their valuable timber. Although natural regeneration is often the preferred option for oak stand establishment in many regions of Central Europe, planting and...
Article
Full-text available
Cluster planting of oaks (Quercus robur and Quercus petraea) was introduced to central Europe in the 1980s and 1990s as an economic and ecological alternative to the traditional and costly row planting for re-afforestation of wind-thrown and clear-cut areas. Clusters comprising 20–30 seedlings are either ‘nests’ (nest planting) with very dense spac...
Article
Full-text available
Several severe drought events have been reported in southern Europe during recent decades. Drought has been found to increase the mortality of the southernmost populations of Scots pine forests in Mediterranean countries and in dry inner-alpine valleys. Therefore the ongoing global climate change is likely to endanger Scots pine in future decades....
Article
Full-text available
This paper describes the role of traditional ecological knowledge and wisdom of the Monpa tribe in the management of natural resources like water, soil and forest in the high altitudes of the Eastern Himalayas. The traditional water resource management practices are highly diversified and have multipurpose uses. People have developed irrigation sys...

Questions

Questions (7)
Question
We often struggle to select the “best” statistical modeling solution in ecological research. The ease of doing complex statistics like generalized linear mixed models (GLMM) in R with advanced computers revolutionizes our computing ability. Still, if I dig deep inside, sometimes I feel that following “all” preconditions for model selection is challenging. For example, it mainly happens when the target variable follows a nonlinear distribution in which current software and programming environments like R, Stata, SPSS, or SAS do not provide a perfect distribution function of the target variable. As a result, we often need an “approximate” distribution for the target variable in the modeling. It may further lead to the wrong decision on the selection of the link function, which can violate the assumption of linearity between transformed expected response and explanatory variables. Recently, we have faced a significant problem in studying the influence of multiple biotic and abiotic variables on the crown dieback of trees in urban and peri-urban forests (n = 2968 trees). The crown dieback followed a bimodal nonlinear distribution and each explanatory variable had different exponential probability distribution. As a result, traditional techniques, like GLMM, could not be used after having a lengthy discussion, literature review, and a lot of “playing” with R!
Some statisticians suggest using generalized additive modeling (GAM) in this situation. However, my colleagues and I will be new to GAM, so we must first spend some time understanding the theory and technicalities.
Therefore, my questions to the scientific community are:
1. When to use GAM?
2. What should be the preconditions of the data, if any?
3. Is there any good open access repository where we can learn more about using GAM, case studies, data, or freely available code?
Your support will be highly appreciated.
Question
Myself and our colleagues in our research group is intrigued by this question. In the Millennium Ecosystem Assessment we did not find any specific mention of the "resilience" as an ecosystem service. We know from the teaching of C.S. Holling that ecological resilience in a forest is the capacity of forest to resist and recover from a disturbance such as drought, fire, storm etc. We can postulate a thesis here that resilience is a property of ecosystem which is also related to well being of human and other organisms. A less resilient forest "may" not provide multiple ecosystem services than a high resilient forest. Several ground breaking research in the field of ecology had proven that high biodiversity is related to high resilience of the ecosystem. Till, we may argue that this may not be always be a general trend in all types of ecosystem. Habitat provisions for biodiversity is considered as a supporting ecosystem service, hence, indirectly related to resilience. However, as I mentioned, resilience may not be always related to high diversity but with many other factors such as traits of the organisms, type and magnitude of stressors, and availability of resources among others. Therefore, biodiversity should not be a direct proxy of resilience in all types of situation. In this case can we say that resilience, which is a property of ecosystem, should be treated as a direct component for the supporting ecosystem service? Discussions, comments and citations of relevant literature on this topic will be highly welcomed.
Question
Hi, we aim to "quantify" cultural ecosystem services from urban forests of our study area (Karlsruhe, Germany). We know that cultural ecosystem services are difficult to quantify as they are often qualitative and have intangible significance. Our approach is to first do a detail survey on public and stakeholders' perception and preferences on selected cultural ecosystem services using questionnaire survey and Likert's scale of response. Then, we want to use our data from the questionnaire survey to develop a scoring systems. Do you know any method which can be helpful to us? Or, do you know how to valuate cultural ecosystem services? In addition to questionnaire survey, we also have data from urban forest plots on forest structure and composition. We followed the guidelines from i-tree-eco software's handbook and UFORE model developed by the US Forest Service (David Nowak). We will really appreciate if you can provide us some literature or provide some suggestions on methods to quantify cultural ecosystem services.
Question
I know this question is very general. However, answers based on your past experience will help me to plan. I intend to keep at least one field botanist with local expertise in the team. The focal areas are Western Ghats and Eastern Himalayas in India. What would be the best time for survey in terms of logistic as well as vegetation? Suggestions will be appreciated.

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Projects (6)
Project
Wärmere, trockenere Sommer erhöhen jetzt auch in Deutschland das Waldbrandrisiko. In den letzten beiden Jahren kam es mehrfach zu großflächigen Bränden, besonders aber auch zu einer Vielzahl von kleineren Waldbränden. Dieser steigenden Waldbrand-Gefahr steht ein Mangel an Wissen gegenüber, welcher sowohl die Forstpraxis, als auch die Feuerwehren und andere Organisationen der Gefahrenabwehr betrifft. Dies zeigt sich auch in der mangelnden Ausbildung in der Bekämpfung von Waldbränden. Im vorgeschlagenen Projekt ErWiN sollen wichtige Grundlagen für den wissens-basierten Umgang mit Waldbränden in den Bereichen Waldbau und Brandbekämpfung geschaffen werden. Vor diesem Hintergrund fokussiert sich das Teilprojekt der KIT-Institute ITAS und IMK-IFU auf die Restaurierung der durch Waldbrände in Brandenburg geschädigten Wälder. Im Einzelnen zielt es darauf ab: 1) die Stockausschlagfähigkeit, das Wachstum und die ökophysiologische Leistungsfähigkeit mehrerer Baumarten nach einem Waldbrand zu vergleichen, 2) das Wachstum und die Vitalität von Sämlingen und Setzlingen zu untersuchen, die durch natürliche Verjüngung aus Samen und künstliche Verjüngung durch Pflanzung gewachsen sind, 3) den Einfluss der Waldkomposition und -struktur und mehrerer anderer abiotischer Variablen auf die Verjüngung nach einem Brand zu ermitteln, 4) verschiedene Arten der künstlichen Verjüngung (z.B. Trupp- vs. Reihenpflanzung) zu vergleichen und 5) die Keimfähigkeit und das Wachstum nach der Keimung der zehn häufigsten Baumarten unter unterschiedlichem Hitzestress in Böden zu quantifizieren. Es werden Felddatensammlungen, Pflanzversuche an verbrannten Waldstandorten und Keimversuche im Gewächshaus durchgeführt. Die Ergebnisse dieses Teilprojekts werden den Förstern helfen, Pläne zur Wiederherstellung von durch Brände geschädigten Standorten zu entwickeln.
Project
This IUFRO Task Force is dedicated to providing the scientific basis for transforming forest landscapes (FLs) to climate-resilient land-use systems that fulfil the complete spectrum of ecosystem service (ES) requirements of current and future societies. This includes the following activities of (1) designing scenarios and projections for future FL development under climate change scenarios and varying societal requirements for different regions of the globe, (2) exploring best practice approaches (BPA) covering the sociopolitical, ecological and economic dimensions of landscape transitions, and (3) developing suitable FL outreach and education materials as well as Research and Development (R&D) schemes for addressing the needs of different stakeholder groups. See also IUFRO spotlight 3/2020 at: https://www.iufro.org/publications/iufro-spotlights/article/2020/03/23/iufro-spotlight-76-transforming-forest-landscapes-to-meet-current-and-future-needs-and-challenges/ Background: Forest landscapes (FLs), dominated by forests and often embedded with other land uses, contribute to many sustainable development goals (SDGs) and provide multiple essential ecosystem services (ES). These include provisioning, regulating, supporting, and cultural services. In particular, for rural populations, FLs are often the basis for the local economy and social identity. However, FLs are under pressure from the loss and degradation of forest area and conversion to other land uses, as well as environmental and climate change. As a result, societies worldwide may face diminishing levels of ecosystem services from FLs on a global scale. Combined strategies for FL preservation, restoration and adaptive management are needed to prevent significant losses of FL ecosystems and their benefits.