Computational analysis of the effects of light gradients and neighbouring species on foliar nitrogen

Foliar nitrogen is one of the key traits determining the photosynthetic capacity of trees. It is influenced by many environmental factors that are often confounded with the photosynthetic photon flux density (PPFD), which alone strongly modifies the nitrogen content and other foliar traits. We combined field measurements and computational estimates of light transmittance in 3D stands with different combinations of Scots pine (Pinus sylvestris) and silver birch (Betula pendula) to decouple the effect of PPFD from other potential effects exerted by the species of neighbouring trees on the leaf nitrogen content per unit leaf area (Narea) and leaf mass per area (LMA). Independent of the level of PPFD, silver birch had a significantly lower Narea and LMA when Scots pine was abundant in its neighbourhood compared with the presence of conspecific neighbours. In Scots pine, Narea and LMA were only dependent on PPFD and the branching order of shoots. In both species, the relationships between PPFD and Narea or LMA were nonlinear, especially at intermediate levels of PPFD. The levels of PPFD did not show any dependence on the species of the neighbouring trees. The responses of silver birch suggest that the species composition of the surrounding stand can influence foliar nitrogen, independent of the level of PPFD within the canopy.Foliar nitrogen is one of the key traits determining the photosynthetic capacity of trees. It is influenced by many environmental factors that are often confounded with the photosynthetic photon flux density (PPFD), which alone strongly modifies the nitrogen content and other foliar traits. We combined field measurements and computational estimates of light transmittance in 3D stands with different combinations of Scots pine (Pinus sylvestris) and silver birch (Betula pendula) to decouple the effect of PPFD from other potential effects exerted by the species of neighbouring trees on the leaf nitrogen content per unit leaf area (Narea) and leaf mass per area (LMA). Independent of the level of PPFD, silver birch had a significantly lower Narea and LMA when Scots pine was abundant in its neighbourhood compared with the presence of conspecific neighbours. In Scots pine, Narea and LMA were only dependent on PPFD and the branching order of shoots. In both species, the relationships between PPFD and Narea or LMA were nonlinear, especially at intermediate levels of PPFD. The levels of PPFD did not show any dependence on the species of the neighbouring trees. The responses of silver birch suggest that the species composition of the surrounding stand can influence foliar nitrogen, independent of the level of PPFD within the canopy.Foliar nitrogen is one of the key traits determining the photosynthetic capacity of trees. It is influenced by many environmental factors that are often confounded with the photosynthetic photon flux density (PPFD), which alone strongly modifies the nitrogen content and other foliar traits. We combined field measurements and computational estimates of light transmittance in 3D stands with different combinations of Scots pine (Pinus sylvestris) and silver birch (Betula pendula) to decouple the effect of PPFD from other potential effects exerted by the species of neighbouring trees on the leaf nitrogen content per unit leaf area (Narea) and leaf mass per area (LMA). Independent of the level of PPFD, silver birch had a significantly lower Narea and LMA when Scots pine was abundant in its neighbourhood compared with the presence of conspecific neighbours. In Scots pine, Narea and LMA were only dependent on PPFD and the branching order of shoots. In both species, the relationships between PPFD and Narea or LMA were nonlinear, especially at intermediate levels of PPFD. The levels of PPFD did not show any dependence on the species of the neighbouring trees. The responses of silver birch suggest that the species composition of the surrounding stand can influence foliar nitrogen, independent of the level of PPFD within the canopy.Peer reviewe

Improving nursing methods by using thermal imaging: Observations by CAT S60 mobile phone

The purpose of this preliminary study was to examine, how thermal imaging could help in advancing nursing methods and offer some new usage targets of thermal imaging for the behoof of a patient. By using CAT S60 cellular phone with an inbuilt Flir thermal camera, thermal pictures were taken from voluntary subjects in order to find out if thermal imaging with CAT S60 phone could help in treatment of a patient. Thermal camera images were taken in order to find out temperature changes in whole body, limbs and extremities. By using thermal imaging in nursing the beginning of treatment could be hastened and the monitoring of the state of a patient would be more efficient thus improving the prognosis of a patient. The benefit of the method is, that it is non-invasive, cheap and easy to use (inside a cellular phone) thus being a clear advantage.  The results of different usage methods seen in thermal images suggest that thermal imaging with CAT S60 phone could be used to improve nursing methods and may also for its part to help in diagnosis. The present preliminary observations via thermal images showed, that the resolution of CAT S60 phone was sufficient to detect changes in human body temperature in home life. This may suggest the usage of the CAT S60 phone in home care services.The purpose of this preliminary study was to examine, how thermal imaging could help in advancing nursing methods and offer some new usage targets of thermal imaging for the behoof of a patient. By using CAT S60 cellular phone with an inbuilt Flir thermal camera, thermal pictures were taken from voluntary subjects in order to find out if thermal imaging with CAT S60 phone could help in treatment of a patient. Thermal camera images were taken in order to find out temperature changes in whole body, limbs and extremities. By using thermal imaging in nursing the beginning of treatment could be hastened and the monitoring of the state of a patient would be more efficient thus improving the prognosis of a patient. The benefit of the method is, that it is non-invasive, cheap and easy to use (inside a cellular phone) thus being a clear advantage.  The results of different usage methods seen in thermal images suggest that thermal imaging with CAT S60 phone could be used to improve nursing methods and may also for its part to help in diagnosis. The present preliminary observations via thermal images showed, that the resolution of CAT S60 phone was sufficient to detect changes in human body temperature in home life. This may suggest the usage of the CAT S60 phone in home care services

Thermal imaging in skin trauma evaluation: observations by CAT S60 mobile phone

The purpose of this study was to evaluate the usability of a mobile phone with inbuilt thermal camera in wound imaging for medical purposes. Thermal imaging could help in evaluating wound healing and in assisting doctors in diagnose making. By using CAT S60 smart phone with an inbuilt Flir thermal camera, thermal pictures from skin wounds and lower limbs were taken from six people in order to find out if thermal imaging could help the treatment and diagnosis of a patient. Thermal images were taken in order to find and visualize temperature changes (being normally invisible) in skin damage areas including deep skin damages especially from limbs and extremities. By using thermal imaging the beginning of treatment could be hastened and the monitoring of the state of a patient would be more efficient thus improving the prognosis of a patient. The thermal pictures taken from skin damages suggest that thermal imaging with CAT S60 smart phone can be used to improve nursing methods and may also help in diagnosis. Non-invasive thermal imaging may be a valuable asset and for its part hasten the beginning of treatment. The resolution and properties of CAT S60 smart phone was sufficient to detect skin damage temperature changes. This may suggest the usage of the CAT S60 smart in hospital, emergency ward and in home care services.The purpose of this study was to evaluate the usability of a mobile phone with inbuilt thermal camera in wound imaging for medical purposes. Thermal imaging could help in evaluating wound healing and in assisting doctors in diagnose making. By using CAT S60 smart phone with an inbuilt Flir thermal camera, thermal pictures from skin wounds and lower limbs were taken from six people in order to find out if thermal imaging could help the treatment and diagnosis of a patient. Thermal images were taken in order to find and visualize temperature changes (being normally invisible) in skin damage areas including deep skin damages especially from limbs and extremities. By using thermal imaging the beginning of treatment could be hastened and the monitoring of the state of a patient would be more efficient thus improving the prognosis of a patient. The thermal pictures taken from skin damages suggest that thermal imaging with CAT S60 smart phone can be used to improve nursing methods and may also help in diagnosis. Non-invasive thermal imaging may be a valuable asset and for its part hasten the beginning of treatment. The resolution and properties of CAT S60 smart phone was sufficient to detect skin damage temperature changes. This may suggest the usage of the CAT S60 smart in hospital, emergency ward and in home care services

Evaluation of importance of sapwood senescence on tree growth using the model Lignum.

The effects of two alternative formulations of sapwood senescence on the behavior of model LIGNUM (with parameter values adjusted for Scots pine growing southern Finland) were studied. The two alternatives were: autonomous sapwood senescence assuming a maximum age for the tree ring and sapwood senescence that is controlled by the mortality of foliage. For the latter alternative two hypothetical further mechanisms were stipulated. All the formulations were implemented in LIGNUM. Simulations were made with all model variants for fertile and poor soil conditions using high, normal and low rates of foliage mortality. The simulation results were compared against of a data set consisting of 11 open grown Scots pine trees from southern Finland. Observations of heartwood proportion were used in this study. They show that heartwood starts to increase in trees from age of approximately 20 years onwards. The simulation results showed no differences between fertile and poor soil conditions as regards heartwood formation. Of the variants of foliage controlled sapwood senescence the one where death of sapwood in a tree segment induces sapwood senescence in the tree parts below only slightly was the best. This and the autonomous sapwood senescence corresponded equally well to the observations. In order to make more refined conclusions additional data and simulations are necessary

A study of crown development mechanisms using a shoot-based tree model and segmented terrestrial laser scanning data

Background and Aims: Functional-structural plant models (FSPMs) allow simulation of tree crown development as the sum of modular (e.g. shoot-level) responses triggered by the local environmental conditions. The actual process of space filling by the crowns can be studied. Although the FSPM simulations are at organ scale, the data for their validation have usually been at more aggregated levels (whole-crown or whole-tree). Measurements made by terrestrial laser scanning (TLS) that have been segmented into elementary units (internodes) offer a phenotyping tool to validate the FSPM predictions at levels comparable with their detail. We demonstrate the testing of different formulations of crown development of Scots pine trees in the LIGNUM model using segmented TLS data. Methods: We made TLS measurements from four sample trees growing in a forest on a relatively poor soil from sapling size to mature stage. The TLS data were segmented into intenodes. The segmentation also produced information on whether needles were present in the internode. We applied different formulations of crown development (flushing of buds and length of growth of new internodes) in LIGNUM. We optimized the parameter values of each formulation using genetic algorithms to observe the best fit of LIGNUM simulations to the measured trees. The fitness function in the estimation combined both tree-level characteristics (e.g. tree height and crown length) and measures of crown shape (e.g. spatial distribution of needle area). Key Results: Comparison of different formulations against the data indicates that the Extended Borchert- Honda model for shoot elongation works best within LIGNUM. Control of growth by local density in the crown was important for all shoot elongation formulations. Modifying the number of lateral buds as a function of local density in the crown was the best way to accomplish density control. Conclusions: It was demonstrated how segmented TLS data can be used in the context of a shoot-based model to select model components.Peer reviewe

Components of functional-structural tree models

Peer reviewe

Application of the functional-structural tree model LIGNUM to sugar maple saplings (Acer saccharum Marsh) growing in forest gaps

LIGNUM is a functional-structural model that represents a tree using four modelling units which closely resemble the real structure of trees: tree segments, tree axes, branching points and buds. Metabolic processes are explicitly related to the structural units in which they take place. Here we adapt earlier versions of LIGNUM designed to model growth of conifers for use with broad-leaved trees. Two primary changes are involved. First, the tree segment for broad-leaved trees consists of enclosed cylinders of heartwood, sapwood and bark. Leaves consisting of petioles and blades are attached to the segments. Secondly, axillary buds and rules governing their dormancy are included in the model. This modified version of LIGNUM is used to simulate the growth and form of sugar maple saplings in forest gaps. The annual growth of the model tree is driven by net production after respiration losses are taken into account. The production rate of each leaf depends on the amount of photosynthetically active radiation it receives. The radiation regime is tracked explicitly in different parts of the tree crown using a model of mutual shading of the leaves. Forest gaps are represented by changing the radiation intensity in different parts of the model sky. This version of LIGNUM modified for use with broad-leaf, deciduous trees and parameterized for sugar maple, yields good simulations of growth and form in saplings from different forest gap environments

Evaluating CENTURY and Yasso soil carbon models for CO2 emissions and organic carbon stocks of boreal forest soil with Bayesian multi-model inference

We can curb climate change by improved management decisions for the most important terrestrial carbon pool, soil organic carbon stock (SOC). However, we need to be confident we can obtain the correct representation of the simultanous effect of the input of plant litter, soil temperature and water (which could be altered by climate or management) on the decomposition of soil organic matter. In this research, we used regression and Bayesian statistics for testing process-based models (Yasso07, Yasso15 and CENTURY) with soil heterotrophic respiration (Rh) and SOC, measured at four sites in Finland during 2015 and 2016. We extracted climate modifiers for calibration with Rh. The Rh values of Yasso07, Yasso15 and CENTURY models estimated with default parameterization correlated with measured monthly heterotrophic respiration. Despite a significant correlation, models on average underestimated measured soil respiration by 43%. After the Bayesian calibration, the fitted climate modifier of the Yasso07 model outperformed the Yasso15 and CENTURY models. The Yasso07 model had smaller residual mean square errors and temperature and water functions with fewer, thus more efficient, parameters than the other models. After calibration, there was a small overestimate of Rh by the models that used monotonic moisture functions and a small generic underestimate in autumn. The mismatch between measured and modelled Rh indicates that the Yasso and CENTURY models should be improved by adjusting climate modifiers of decomposition or by accounting for missing controls in, for example, microbial growth.Peer reviewe

The LIGNUM functional-structural tree model

The aim of this thesis was to construct a single tree model that builds a bridge between traditional process based tree models and detailed, three-dimensional architectural tree models. The result of the thesis, the functional-structural tree model LIGNUM, integrates both the functional and the structural aspects of woody arborescent plants in a single generic modelling framework. The thesis consists of five articles and the summary part. The first article presents the model structure of LIGNUM based on simple recurring botanical units, their metabolic processes and the allocation of photosynthates on the basis of the carbon balance resolved according to the specific growth potential in different parts of the tree crown. The model is applied to young Scots pine (Pinus sylvestris L.). The second article studies alternative formulations of sapwood senescence in Scots pine. The third article presents an improvement in assessing solar radiation absorption on the basis of the mutual shading of tree segments. The fourth article adapts the LIGNUM model to deciduous species with sugar maple (Acer saccharum Marsh) as an example. The fifth article introduces Lindenmayer systems for defining the architectural development of the tree crown. The central problem in process-based tree models has been resource capture and allocation in a dynamically growing tree. The main contribution of this thesis is to present a solution to how photosynthates can be allocated among possibly thousands of botanical units in a tree. The LIGNUM model can simulate the three-dimensional architectural development of a tree crown, keep track of each elementary functional unit, define their local capacity to produce and use resources, and determine the interactions with each other and the external environment