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* Seminari CEMFORSeminari CEMFOR

Time: 11:30 am

Quim Canelles

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CEMFOR SEMINAR – Quim Canelles

Speaker: Quim Canelles (CTFC)

Title: Parametrització de models dinàmics de vegetació a escala de paisatge

Abstract: El model Medfire integra els principals processos paisatgístics que impulsen la dinàmica de paisatges a Catalunya en un context del canvi global. Inclou els principals factors de canvi de paisatge per estudiar les seves interaccions espai-temps: les pertorbacions naturals (principalment incendis), les estratègies de gestió forestal, els processos d’aforestació i successió natural i el creixement de la massa forestal. En el seminari proposat, intentaré resumir l’aproximació que hem fet a aquests procesos, la metodologia emprada, el procés de cal·libració i la conseqüent integració al model Medfire.

CEMFOR SEMINAR – Mo Zhou

Speaker: Mo Zhou (School of Natural Resource, West Virginia University)

Title: New Advances in Markov Decision Process Models for Forest Management: Multi-criteria and Risk-sensitive Decision Making

Abstract: This work synthesis two recent studies extending the classic linear-programming formulations of Markov Decision Process (MDP) models to, respectively, handle multiple objectives and reflect risk preference, in forest decision making. One study incorporated goal programming in MDPs with both average and discounted criteria to deal with multiple, often non commensurable and conflicting, objectives. The other adapted mean-variance or certainty equivalent optimization to MDPs with average rewards to reflect some consequences of the risk attitude of forestry decision makers. Both studies were applied to data for mixed softwood and hardwood forests in the southern United States, with multiple financial and ecological criteria. The results show that given equal weights for normalized criteria, minimum deviations from the highest diversity of tree size and species were achieved at the cost of, on average, one third of decline of other criteria from their maximum levels. Compared with risk neutrality or risk seeking, financial risk aversion induced shorter cutting cycles and, besides reducing expected annual financial returns and production, also lowered the expected diversity of tree species and size, stand basal area, stored CO2e, and old growth area.

CEMFOR SEMINAR – Jennie Sandtröm / Frederick Carlsson

Speakers: Jennie Sandtröm & Frederick Carlsson

Title: Rocky pine forests in the High Coast Area (Sweden) and Wood Fungi and Forest Fire in a boreal context

Abstract: Almost all forests in Sweden are managed to some extent, only a small fraction can be considered natural. However, low productive forests, mostly without formal protection and privately owned, has rarely been managed and can have old-growth characteristics. Pine (Pinus sylvestris) forests in the High Coast Area (World Heritage Area) are extremely rocky and nutrient poor. We have investigated the structure, dynamics, human impact and fire history in this extreme environment. This was done by sampling and measuring size, age, fire scars, dead wood amount and quality at eight rocky pine stands. The structure is diverse (sizes and ages, Dead wood) but the density low. Frequent small fires have occurred and many of them (13) during the 1600s. The rocky pine forests in the High Coast Area are most likely undisturbed forests with low human impact, exhibiting several old-growth characteristics and can be a valuable habitat for organisms connected to sun-exposed DW. Wood fungi are the most important group of decomposers in boreal forests, and can be regarded as the “engineers of dead wood”. Forest fire has been the main disturbance in these forests and thus, boreal species has had to adapt to repeated fires. Industrialization drastically changed forestry and since the beginning of the 1900´s, forest fires have become very scarse, species dependent on repeated fires has consequently gone extinct or can be considered threatened or near threatened. The loss of wood fungi biodiversity can have a major impact on many other species due to their important role in dead wood dynamics. Our studies has been focusing on several aspects of wood fungi – forest fire interaction, including adaptation, community dynamics and combative interactions. Species that can be related to forest fire has adapted and is strongly favored by the disturbance. Our research can be used for restoration purposes, planning and performing restoration fires

CEMFOR SEMINAR – Pere Casals

Speaker: Pere Casals (CTFC-CEMFOR)

Title: Understory woody resprouting strategies after prescribed fires

Abstract: The capacity of a plant species to resprout after destruction of most of its aboveground biomass is an important trait for its persistence. However, different mechanisms may operate at different levels after fire to reestablish individuals from each species and better compete for the acquisition of resources. trade-offs between growth investment for better light acquisition and resource allocation for resisting additional stress, such as recurrent fires, browsing or insect injuries, may determine the exit of some species over others short-term after underburning. Tacking advantage of the richness of functional traits of Mediterranean forest understory, this study aims to discuss the expression of different plant functional traits on the resprouting vigor after prescribed underburning in relation to the specific characteristics of shrub individuals, microsite light availability, and intensity and season of fire.
At individual level, in addition to pre-fire shrub size, light availability seems to be a strong driver of resprouting vigor three years after underburnings. Bark investment index at the species level contributes to explain the performance of resprouts. Hence, leaf area, specific leaf area and bark investment are inter- and intraspecific traits clearly related to the expression of resprouting vigor. At plot scale, the number and performance of resprouts of the studied shrub species were lower in fall burns than in spring ones. As a conclusion, our study suggests that the phenological and physiological status of shrub individuals went the perturbation occurs may be crucial for its reestablishment. This knowledge may assist in the decision-making process for the management of understory forests in relation to site characteristics and plant composition and structure.

CEMFOR SEMINAR – Aleksi Lehikoinen

Speaker: Aleksi Lehikoinen (University of Helsinki)

Title: : Abundance changes of birds in Europe: impact of climate, land use and life histories

Abstract: Climate change has suggested to shift species distribution areas towards north, but also other anthropogenic factors can influence population. In this presentation, I show examples based on long-term monitoring how abundances of bird species have changed in relation to climate change, species habitat preferences and human land use. In addition, we have also investigated can protected areas mitigate impacts of climate change. Since many bird species are migratory it is important to investigate changes during both breeding and wintering season. One of the strongest climate driven changes are the shifts in wintering abundances of waterbirds. I also present preliminary results where changes in wintering bird communities in relation to climate change have been studies across Europe from Catalonia to Finland.

CEMFOR SEMINAR – Kate Giljohann

Speaker: Kate Giljohann (University of Melbourne, Australia)

Title: A demographically effective measure of population size for disturbance-prone ecosystems

 

Abstract

Stochastic disturbances, such as fire, are important in many ecosystems. Disturbances can drive population dynamics; stimulating large changes in population size and structure. Understanding how population structure at one point in time influences future population size is key to making realistic estimates of population changes in disturbance-prone ecosystems.  Yet how population structure interacts with disturbance regimes is rarely considered in conservation management.

A useful theory to account for the influence of population structure on future population size is the stochastic equivalent ratio. However, it is unclear whether this theory applies when stochasticity is large, such as in fire-prone environments.

Using a population model for a fire-killed obligate seeder from semi-arid Australia, I explore the utility of the stochastic equivalent ratio and ask, can the ratio: i) indicate the potential for future population growth? ii) identify appropriate fire regimes? and iii) estimate the abundance of seedlings that will emulate the trajectory of a reference population?

The method I evaluate, and then generalize, has wide applicability and great potential for achieving future plant and animal population goals when stochastic disturbances drive population dynamics.

CEMFOR SEMINAR – Pablo Cruz

Speaker: Pablo Cruz (Universidad Mayor de Chile).

Subject: Exploring collaboration between CTFC and UMayor-Oterra

OTERRA es un centro de estudios de recursos naturales perteneciente a la escuela de ingeniería forestal de la U. Mayor. Posee 9 investigadores tiempo completo, laboratorios y equipos propios y sus actividades se financian con fondos externos a la Universidad, tanto del sector público como privado.

R workshop – Aitor Ameztegui

Organizer: Aitor Ameztegui (CTFC-CREAF)

Title: Using packages ‘tidyr’ and ‘dplyr’

 

CEMFOR SEMINAR – Antoine Cabon

Speaker: Antoine Cabon (Ph.D. student, CTFC-CREAF)

Title: The ecohydrological equilibrium hypothesis allows quantifying the soil water supply of drought prone forests.

Abstract: In water-limited ecosystems, such as Mediterranean ones, the amount of water plants can access (i.e. the Soil Water Supply, SWS) is a key determinant of forest demography (e.g. tree growth and mortality) and function (e.g. water and carbon fluxes).

Although the link between soil moisture (θ) and soil water extractability by plants can be modelled through pedotransfer functions, the estimation of SWS is limited by the difficulty to measure the plants rooting depth (Z) and their Fine Roots Distribution (FRD) in the soil profile.

Here we estimate Z and FRD for different forest plots located in Catalonia (Northeast Spain), where θ or transpiration (E, approached by
sap flow measurements) observations were available, using simplified representation of plant hydraulics and the Eco-Hydrological Equilibrium (EHE) hypothesis. We assume that forest stands conform to this hypothesis and that their root system is therefore optimized in order to maximize transpiration within the limits of acceptable drought stress, characterized using species-specific critical levels of leaf water potentials (ψ).

We simulate ψ, E and θ for different combinations of Z and FRD with a simple water balance model and use the simulations to approach the local actual values of Z and FRD by 1) hypothesizing optimized species root system and by 2) calibrating our model against E or θ observations. Estimates from both methods were in close agreement when water was a most limiting factor, therefore sustaining our initial hypothesis.

Our method has the potential to palliate the lack of data concerning the root system of drought prone forests using only information on stand structure and plant hydraulic properties and could therefore enhance the modelling of water fluxes at large spatial scales.

 

CEMFOR SEMINAR – Aitor Ameztegui

Speaker: Aitor Ameztegui (Marie Curie fellowship, CREAF)

Title: Managing stand density to enhance the adaptability of Scots pine stands to climate change: a modelling approach

Abstract: La mayoría de los modelos climáticos para la región mediterránea predicen periodos de sequía más frecuentes e intensos, que pueden afectar al crecimiento y mortalidad de los árboles en amplias zonas de su distribución actual. Uno de los tratamientos selvícolas que se baraja para mitigar los impactos del cambio climático es reducir la densidad de arbolado mediante claras. Sin embargo, aún no está claro cómo responderán las masas forestales a diferentes regímenes de claras en función del escenario climático, ni conocemos bien la dinámica post-clara del balance hídrico. En este estudio exploramos estos aspectos para masas de pino albar (Pinus sylvestris) mediante modelización, acoplando un modelo de dinámica forestal con un modelo mecanístico de humedad del suelo y estrés hídrico. Nuestros resultados muestran la existencia de trade-off entre el incremento de productividad y la ganancia en disponibilidad hídrica provocada por las claras. Además, dichos mecanismos dependen de la estación y el clima, por lo que no sería recomendable aplicar recetas generalistas sin tener en cuenta estos factores.