The relationship between form and function in trees is the subject of a longstanding debate in forest ecology and provides the basis for theories concerning forest ecosystem structure and metabolism. Trees interact with the wind in a...
moreThe relationship between form and function in trees is the subject of a longstanding debate in forest ecology and provides the basis for theories concerning forest ecosystem structure and metabolism. Trees interact with the wind in a dynamic manner and exhibit natural sway frequencies and damping processes that are important in understanding wind damage. Tree-wind dynamics are related to tree architecture, but this relationship is not well understood. We present a comprehensive view of natural sway frequencies in trees by compiling a dataset of field measurement spanning conifers and broadleaves, tropical and temperate forests. The field data show that a cantilever beam approximation adequately predicts the fundamental frequency of conifers, but not that of broadleaf trees. We also use structurally detailed tree dynamics simulations to test fundamental assumptions underpinning models of natural frequencies in trees. We model the dynamic properties of greater than 1000 trees using a ...
In order for wood to be used to make composite products, feedstock originating from trees and logs must first be obtained, sometimes as a by-product of other primary wood processing operations. This chapter provides a summary of primary...
moreIn order for wood to be used to make composite products, feedstock originating from trees and logs must first be obtained, sometimes as a by-product of other primary wood processing operations. This chapter provides a summary of primary wood processing as it relates to the production of the raw materials used in wood composites. It begins with an overview of peeling and sawmilling, which are used to provide the materials for solid wood composites. It then describes the production of chips, flakes and fibres that are used to manufacture composite panels. Finally, a brief overview is presented on the production of nanocellulose from wood.
To maximize utilization of our forest resources, detailed knowledge of wood property variation and the impacts this has on end-product performance is required at multiple scales (within and among trees, regionally). As many wood...
moreTo maximize utilization of our forest resources, detailed knowledge of wood property variation and the impacts this has on end-product performance is required at multiple scales (within and among trees, regionally). As many wood properties are difficult and time-consuming to measure our knowledge regarding their variation is often inadequate as is our understanding of their responses to genetic and silvicultural manipulation. The emergence of many non-destructive evaluation (NDE) methodologies offers the potential to greatly enhance our understanding of the forest resource; however, it is critical to recognize that any technique has its limitations and it is important to select the appropriate technique for a given application. In this review, we will discuss the following technologies for assessing wood properties both in the field: acoustics, Pilodyn, Resistograph and Rigidimeter and the lab: computer tomography (CT) scanning, DiscBot, near infrared (NIR) spectroscopy, radial samp...
An inventory of fresh logging wounds from treatment implementation was performed in a regional green-tree retention experiment in Oregon and Washington. The DEMO (Demonstration of Ecosystem Management Options) study contains six...
moreAn inventory of fresh logging wounds from treatment implementation was performed in a regional green-tree retention experiment in Oregon and Washington. The DEMO (Demonstration of Ecosystem Management Options) study contains six treatments replicated in six blocks: (1) 100% retention (control), (2) 75% aggregated retention, (3) 40% dispersed retention, (4) 40% aggregated retention, (5) 15% dispersed retention, and (6) 15% aggregated retention. Over all blocks and treatments, Douglas-fir (Pseudotsuga menziesii) and western hemlock (Tsuga heterophylla) comprised 74.9% of all measured trees, and the proportion of trees damaged was similar for both species. Suppressed trees tended to be more susceptible to damage than were trees in other crown classes. A greater proportion of trees in the dispersed retention treatments were damaged than in the aggregated treatments. Only in the two dispersed retention treatments were levels of damage significantly different from the control (P < 0.05...
Understanding tree stability under self-weight and applied loads from wind and snow is important when developing management strategies to reduce the risk of damage from these abiotic agents. In this paper, linear buckling analysis was...
moreUnderstanding tree stability under self-weight and applied loads from wind and snow is important when developing management strategies to reduce the risk of damage from these abiotic agents. In this paper, linear buckling analysis was conducted using the finite element method to identify the instability modes of a tree structure under a specified set of loads. A non-prismatic elastic circular column of height H was analysed, taking self-weight into account. Various scenarios were considered: column taper, base rigidity, radial and longitudinal stiffness, ellipticity and crown weight. The effect on the critical buckling height was assessed in each case. Validation against closed form solutions of benchmark problems was conducted satisfactorily. The results indicate that column taper, base rigidity and the stiffness/density ratio are particularly important for this problem. Further comparison was made using data from a 15-year old Pinus radiata stand in New Zealand, which contained bo...
Co-innovation can be effective for complex challenges – involving interactions amongst multiple stakeholders, viewpoints, perceptions, practices and interests across programmes, sectors and national systems. Approaches to challenges in...
moreCo-innovation can be effective for complex challenges – involving interactions amongst multiple stakeholders, viewpoints, perceptions, practices and interests across programmes, sectors and national systems. Approaches to challenges in the primary sector have tended to be linear, where tools and outputs are developed by a few, mostly scientists/researchers, and then extended to stakeholders. A co-innovation approach first deciphers and delineates the biophysical, societal, regulatory, policy, economic and environmental drivers, constraints and controls influencing these challenges at multiple levels. Second, stakeholder interactions and perspectives can inform and change the focus as well as help in co-developing solutions to deliver agreed outcomes. However, there is limited systematic and comparative research on how co-innovation works out in different projects. Here we analyse the results of applying a co-innovation approach to five research projects in the New Zealand primary se...
Virot et al. [E. Virot et al., Phys. Rev. E 93, 023001 (2016)10.1103/PhysRevE.93.023001] assert that the critical wind speed at which ⩾50% of all trees in a population break is ≈42 m/s, regardless of tree characteristics. We show that...
moreVirot et al. [E. Virot et al., Phys. Rev. E 93, 023001 (2016)10.1103/PhysRevE.93.023001] assert that the critical wind speed at which ⩾50% of all trees in a population break is ≈42 m/s, regardless of tree characteristics. We show that empirical data do not support this assertion, and that the assumptions underlying the theory used by Virot et al. are inconsistent with the biomechanics of trees.
In order to drive forest sector productivity, an emphasis has been placed on effectively transferring science knowledge to technical foresters. Having a communications plan and engaging the right stakeholders early can induce a rich...
moreIn order to drive forest sector productivity, an emphasis has been placed on effectively transferring science knowledge to technical foresters. Having a communications plan and engaging the right stakeholders early can induce a rich learning environment that strengthens context, knowhow and ensures mechanisms are in place for knowledge to be transferred. Formalized structures such as reports and seminars have evolved to improve the science transfer process, but it appears that the key success factor in enhancing uptake and learning may require an environment that encourages relationship building, particularly trust building between parties in developing informal and formal relationships. Informal interactions, though not often acknowledged in business, foster the conditions conducive to good knowledge exchange – co-ordination, co-operation and communication. Enhancing conditions in which these three aspects grow can lead to increased social capital, changed paradigms and reduced bus...
Timber production from Scots pine forests in Great Britain is forecast to increase over the next 15 years. This Research Note presents the results of a project to develop and test methods for assessing the quality of Scots pine timber...
moreTimber production from Scots pine forests in Great Britain is forecast to increase over the next 15 years. This Research Note presents the results of a project to develop and test methods for assessing the quality of Scots pine timber from measurements on trees ...
ABSTRACT Mechanical stress resulting from wind forces acting on trees can cause a number of direct and indirect effects ranging from microscopic changes in cambial activity through to stem breakage and uprooting. To better understand...
moreABSTRACT Mechanical stress resulting from wind forces acting on trees can cause a number of direct and indirect effects ranging from microscopic changes in cambial activity through to stem breakage and uprooting. To better understand these effects on radial stem growth and wood properties, an experiment was established in a 13-year-old radiata pine (Pinus radiata D Don) stand in which 20 trees were guyed to prevent them from swaying. Radial growth was monitored in these trees and 20 matched controls at monthly intervals for 5 years. The trees were then felled and radial growth, resin features and compression wood were assessed on cross-sectional discs taken at fixed locations up the stem. There was a significant reduction in radial growth at breast height (1.4 m above the ground) in the guyed trees, but an increase in growth immediately above the guying point. A total of 277 resin features were observed in the growth rings formed following guying. The overall frequency of such features was related to height within the stem and annual ring number. No effect of stem guying was found on the incidence of compression wood. Interestingly, the distribution of resin features also did not differ between guyed and un-guyed trees. There was no evidence of a link between stem restraint as a result of guying and the incidence of resin features, suggesting that other factors, such as soil moisture may be more influential.
Determining the Shear Modulus of Sitka Spruce from Torsion Tests Aamir KHOKHAR PhD Student Centre for Timber Engineering, Napier University Edinburgh, UK Dr. Hexin ZHANG Lecturer School of Engineering and the Built Environment, Napier...
moreDetermining the Shear Modulus of Sitka Spruce from Torsion Tests Aamir KHOKHAR PhD Student Centre for Timber Engineering, Napier University Edinburgh, UK Dr. Hexin ZHANG Lecturer School of Engineering and the Built Environment, Napier University Edinburgh, UK ...
on the tree and wood quality of Sitka spruce growing in the United Kingdom. Silva Fennica
In recent years there has been a renewed focus on wood quality, and the recent Forest Growers’ Science and Innovation Plan identified it as the common research priority of both forest growers and wood processors. Variations in the...
moreIn recent years there has been a renewed focus on wood quality, and the recent Forest Growers’ Science and Innovation Plan identified it as the common research priority of both forest growers and wood processors. Variations in the properties of the wood raw material supply affect the quality of the end-products produced by wood processors, which in turn affects their profitability. The forests that will provide the raw material for New Zealand’s domestic processing sector are already in the ground and growing, and a key priority will be to better characterise the wood properties of the trees in these forests to ensure that they are sent to the most appropriate processing stream. New advances in remote sensing and other segregation technologies may help, but they will only be used when the benefits outweigh the cost of implementing them. Understanding the drivers of variation in wood properties and developing strategies for dealing with this variation is important when establishing n...
The extent and sources of variation in the wood quality of Sitka spruce (Picea sitchensis (Bong.) Carr.) were quantified using data collected from 64 stands in northern Britain. These stands were selected on the basis of elevation,...
moreThe extent and sources of variation in the wood quality of Sitka spruce (Picea sitchensis (Bong.) Carr.) were quantified using data collected from 64 stands in northern Britain. These stands were selected on the basis of elevation, latitude, longitude, yield class, initial spacing and the presence or absence of thinning. Dynamic modulus of elasticity (MOE) was calculated from measurements of stress wave velocity made on standing trees and qualitative descriptions were made of stem form. Dynamic MOE of individual trees ranged from 3.81 kN/mm up to 12.29 kN/mm, with a mean of 7.71 kN/mm. Approximately 55 percent of the variation in dynamic MOE was due to differences between individual trees within a site, while 35 percent was due to differences between sites. The remaining 10 percent was due to differences between the measurements made on opposite sides of each tree. Variation in dynamic MOE at the site level was significantly influenced by yield class, elevation as well as by a numbe...
1,2,4 Centre for Timber Engineering, Edinburgh Napier University, UK 3 Forest Science and Resources, Forest Products Commission, Australia 5 Northern Research Station, Forest Research, Forestry Commission, UK ... Abstract: Sitka spruce...
more1,2,4 Centre for Timber Engineering, Edinburgh Napier University, UK 3 Forest Science and Resources, Forest Products Commission, Australia 5 Northern Research Station, Forest Research, Forestry Commission, UK ... Abstract: Sitka spruce (Picea sitchensis) is the ...
Realised genetic gain for radiata pine (Pinus radiata D. Don) was estimated using data from 46 installations of three series of block-plot trials spanning a wide range of site types throughout New Zealand. These trials contained 63 unique...
moreRealised genetic gain for radiata pine (Pinus radiata D. Don) was estimated using data from 46 installations of three series of block-plot trials spanning a wide range of site types throughout New Zealand. These trials contained 63 unique seedlots with different levels of genetic improvement. Realised genetic gain was quantified using two measures of productivity: site index and 300 Index (a measure of volume productivity). The level of genetic improvement of each seedlot was determined by its GF Plus rating, a genetic rating system based on breeding values used for New Zealand radiata pine. There was a positive relationship between GF Plus rating and both productivity measures. Differences of 25% in total standing volume at age 30 years and of 5.6% in site index were found between unimproved (GF Plus 9.9) and highly improved (GF Plus 25) seedlots. Each unit increase in GF Plus rating was associated with a 1.51% increase in volume growth rate. In absolute terms, the magnitude of the...
Given the importance of radiata pine ( Pinus radiata D.Don) to the New Zealand forestry sector, there has been a considerable focus on understanding growth and wood properties in this species. However, for many years research focused on...
moreGiven the importance of radiata pine ( Pinus radiata D.Don) to the New Zealand forestry sector, there has been a considerable focus on understanding growth and wood properties in this species. However, for many years research focused on understanding and enhancing tree growth was not always linked with research into wood quality. Much of the initial work investigating radiata pine wood quality focused on quantifying the extent of variation in key properties of interest, principally density, within and among trees (Cown and McConchie, 1983, Harris, 1965, Palmer et al., 2013) and how these were affected by forest management (Carson et al., 2014, Cown, 1973, Cown, 1974, Cown and McConchie, 1981, Cown and McConchie, 1982). At the same time research into growth looked at how to improve both productivity and profitability. This has resulted in a reduction in rotation length and also silvicultural regimes that were often characterized by heavy and early thinning (James, 1990). The focus of...
ABSTRACT An analysis is presented of spray monitoring data collected during aerial application of Bacillus thuringiensis var. kurstaki in an attempt to eradicate painted apple moth (PAM) (Teia anartoides Walker) from Auckland, New...
moreABSTRACT An analysis is presented of spray monitoring data collected during aerial application of Bacillus thuringiensis var. kurstaki in an attempt to eradicate painted apple moth (PAM) (Teia anartoides Walker) from Auckland, New Zealand. A database was compiled that included measurements of spray droplet density, weather conditions, flight lines from the aircraft global positioning systems, and field bioassay data. SpraySafe Manager (SSM), a GIS-based aerial spray application simulation model was used to calculate predicted deposition across the spray area. Data from GPS systems and spray computers provided information on the consistency of flying and spraying parameters (e.g. flying speed, release height, spray flow rate). Using cards to monitor spray deposition provided a measure of droplet density, a check on droplet size, and an index of biological efficacy. Droplet density data were variable and had a skewed distribution. However, the distribution was approximately normalized by a square root transformation. Only a relatively small amount of variation in droplet density was explained by measured variables. However, there was a reasonable degree of consistency in droplet density between sprays when sampled at fixed locations. Droplet density was significantly decreased by high temperatures (&amp;gt; 20°C) and higher wind speeds. SSM predictions provided no additional explanation of variance in droplet density.
Spiral grain measurements are subject to a high degree of variation and interpretation, depending on the assessment method used. A new measurement approach was tested whereby light was directed through disc samples on a flatbed scanner...
moreSpiral grain measurements are subject to a high degree of variation and interpretation, depending on the assessment method used. A new measurement approach was tested whereby light was directed through disc samples on a flatbed scanner and the deviation along the grain assessed by means of a template to allow the mapping of grain angle variation radially and tangentially within discs. Initial results showed that the approach was valid for green discs up to 35 mm thick and small enough to fit on an A4 scanner. Comparisons with traditional scribing and cleaving methods were favourable, indicating that the light transmission approach could allow much faster and more accurate data acquisition. The possibility of using larger discs would enhance the ability to assess spatial variation in grain angle and minimise the effects of sample reference geometry with respect to the tree axis (disc tilt and parallax). Further work may also be required to ensure that reliable spiral grain values are...
Wind is the major abiotic disturbance in New Zealand's planted forests, but little is known about how the risk of wind damage may be affected by future climate change. We linked a mechanistic wind damage model (ForestGALES) to an...
moreWind is the major abiotic disturbance in New Zealand's planted forests, but little is known about how the risk of wind damage may be affected by future climate change. We linked a mechanistic wind damage model (ForestGALES) to an empirical growth model for radiata pine (Pinus radiata D. Don) and a process-based growth model (CenW) to predict the risk of wind damage under different future emissions scenarios and assumptions about the future wind climate. The CenW model was used to estimate site productivity for constant CO2 concentration at 1990 values and for assumed increases in CO2 concentration from current values to those expected during 2040 and 2090 under the B1 (low), A1B (mid-range) and A2 (high) emission scenarios. Stand development was modelled for different levels of site productivity, contrasting silvicultural regimes and sites across New Zealand. The risk of wind damage was predicted for each regime and emission scenario combination using the ForestGALES model. The ...
Free vibration analysis of a Euler-Bernoulli tapered column was conducted using the finite element method to identify the vibration modes of an equivalent tree structure under a specified set of conditions. A non-prismatic elastic...
moreFree vibration analysis of a Euler-Bernoulli tapered column was conducted using the finite element method to identify the vibration modes of an equivalent tree structure under a specified set of conditions. A non-prismatic elastic circular column of height L was analysed, taking distributed self-weight into account. Various scenarios were considered: column taper, base fixity, radial and longitudinal stiffness (E) and density (ρ) and crown mass. The effect on the first natural frequency was assessed in each case. Validation against closed form solutions of benchmark problems was conducted satisfactorily. The results show that column taper, base fixity and E/ρ ratio are particularly important for this problem. Comparison of predictions with field observations of natural sway frequency for almost 700 coniferous and broadleaved trees from the published literature showed that the model worked well for coniferous trees, but less well for broadleaved trees with their more complicated crow...
Free vibration analysis of a Euler-Bernoulli tapered column was conducted using the finite element method to identify the vibration modes of an equivalent tree structure under a specified set of conditions. A non-prismatic elastic...
moreFree vibration analysis of a Euler-Bernoulli tapered column was conducted using the finite element method to identify the vibration modes of an equivalent tree structure under a specified set of conditions. A non-prismatic elastic circular column of height L was analysed, taking distributed self-weight into account. Various scenarios were considered: column taper, base fixity, radial and longitudinal stiffness (E) and density (ρ) and crown mass. The effect on the first natural frequency was assessed in each case. Validation against closed form solutions of benchmark problems was conducted satisfactorily. The results show that column taper, base fixity and E/ρ ratio are particularly important for this problem. Comparison of predictions with field observations of natural sway frequency for almost 700 coniferous and broadleaved trees from the published literature showed that the model worked well for coniferous trees, but less well for broadleaved trees with their more complicated crow...
... Richmond, BC, Jan 31-Feb 1, 2001. Pojar, J., Klinka, K., Meidinger, DV 1987: Biogeoclimatic ecosystem classification in British Columbia. For. Ecol. Manage., 22, pp. 119-154. Seymour, R. Hunter, M. 1999: Principles of ecological...
more... Richmond, BC, Jan 31-Feb 1, 2001. Pojar, J., Klinka, K., Meidinger, DV 1987: Biogeoclimatic ecosystem classification in British Columbia. For. Ecol. Manage., 22, pp. 119-154. Seymour, R. Hunter, M. 1999: Principles of ecological forestry. ...