Borrowed plant defences: Deterring browsers using a forestry by-product

Published Date
Forest Ecology and Management
15 April 2017, Vol.390:1–7, doi:10.1016/j.foreco.2017.01.013

• Author 

• R.S. Stutz ^,
• B.M. Croak
• O. Leimar
• U.A. Bergvall

• Department of Zoology, Stockholm University, SE-106 91 Stockholm, Sweden

Received 1 December 2016. Revised 12 January 2017. Accepted 13 January 2017. Available online 23 January 2017. 

Highlights

• •
  Plant chemical defences from a forestry by-product can reduce ungulate browsing.
• •
  Birch bark extract protects pine seedlings from browsing by red deer and moose.
• •
  Red deer and moose respond differently when only alternate seedlings are treated.
• •
  Herbivore foraging strategy should be considered in repellent application schemes.

Abstract

Mammalian browsers can cause ecologically and economically significant damage to important tree species, particularly at the vulnerable seedling stage. Some tree species or particular parts of trees are less preferred as a result of chemical defences – harnessing such defences could reduce the appeal of more preferred trees and thus their loss to browsing. We tested the potential of birch bark extract, a forestry by-product, to protect seedlings of Scots pine Pinus sylvestris from two globally significant browsers: moose Alces alces and red deer Cervus elaphus. We quantified the responses by captive animals to extract application as a function of both the distance between seedlings and whether the extract was applied to all or alternate seedlings. Both moose and red deer consumed pine seedlings less frequently when seedlings were treated with birch bark extract, but their responses differed when only alternate seedlings were treated. At inter-seedling distances equivalent to those used in forestry, red deer browsed untreated seedlings more frequently when alternate seedlings were treated than when none were treated (associational susceptibility), whereas moose browsed untreated seedlings less frequently with treated than untreated neighbours (associational refuge). These neighbourhood effects were not evident at inter-seedling distances three times larger or smaller than those used in forestry. There was also no significant difference in the frequency of browsing on treated seedlings in alternate compared to completely treated arrangements at any inter-seedling distance. Red deer removed significantly less foliage from treated than untreated seedlings once browsed. Browsing by moose followed a similar but non-significant trend. The relative number of untreated to treated seedlings browsed was 2:1 for red deer and 4:1 for moose. Red deer used a finer scale of selection than moose for choosing between seedlings, consistent with their smaller body mass. However, the coarser-scale of selection used by moose resulted in consumption of more untreated relative to treated seedlings. Our study highlights the potential of existing plant defensive chemistry, harvested from forestry by-products, to reduce herbivore damage to tree seedlings. We also demonstrate the need to consider both plant associational effects and the foraging strategies of the dominant herbivores in applying repellents.

Keywords

Associational plant effect

Deer

Foraging

Forestry

Plant defence

Repellent

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Fig. 1.

 Table 1

Table 1.

Fig. 2.

 Table 2

Table 2.

Fig. 3.

• DOCX (91K)

Supplementary data 1

• ⁎ 
  Corresponding author.

© 2017 Elsevier B.V. All rights reserved.

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Masalah Pembangunan Tanah Tinggi dan Pengurusannya di Malaysia

Conference Paper (PDF Available) · April 2013 with 9,271 Reads

Conference: Seminar Serantau Ke-2 Pengurusan Persekitaran di Alam Melayu, At Pekanbaru, Volume: 1

• 

  1st Ngai Weng Chan

  24.96 · Universiti Sains Malaysia
• 

  2nd Asyirah Abdul Rahim
• 

  3rd Narimah Samat

  11.93 · Universiti Sains Malaysia
• 

  4th Jamaluddin Md Jahi

Abstract

Di negara tropika, kawasan tanah tinggi merupakan kawasan utama pelancongan, pertanian dan petempatan. Di Malaysia, banyak kawasan tanah tinggi seperti Cameron Highlands, Genting Highlands, Fraser’s Hill, Bukit Larut dan Bukit Bendera merupakan destinasi pelancongan utama. Selain itu, tanah tinggi juga merupakan kawasan pertanian utama, khasnya untuk buah-buahan, sayur-sayuran dan bunga-bungaan. Namun, kawasan tanah tinggi di Malaysia juga merupakan kawasan sensitif dari segi alam sekitar dan ekologi. Tanah tinggi mempunyai cerun curam, punck bukit, flora dan fauna endemik yang terancam, dan komuniti tempatan yang kaya dalam budaya. Antara tarikan utama tanah tinggi ialah iklim yang lebih sejuk berbanding dengan tanah dataran rendah. Akibat pembangunan pesat dan perancangan serta pengurusan yang kurang efektif, kawasan-kawasan tanah tinggi telah mengalami perubahan persekitaran yang negatif. Antara perubahan besar ialah perubahan guna tanah dari hutan ke bandar dan ladang, perubahan unsur iklim, pembandaran dan peningkatan bencana alam.Walaupun banyak perubahan fizikal ini menggambarkan kemajuan dan membawa faedah ekonomi, ianya juga telah membawa impak negatif seperti bahaya dan bencana persekitaran. Antaranya ialah hakisan tanah, tanah runtuh, penyahhutanan, pemusnahan tadahan air, pencemaran alam sekitar, pengenapan sungai dan empangan, dan banjir di kawasan hilir sungai. Pengurusan persekitaran di kawasan tanah tinggi adalah mustahak untuk mengawal kemerosotan persekitaran demi menjaminkan kelestarian. Kertas kerja ini mengkaji isu dan cabaran alam sekitar utama di kawasan tanah tinggi di Malaysia dan cara-cara efektif pengurusannya mengikut model pembangunan lestari.

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Thermal stability of processed PVC/bamboo blends: effect of compounding procedures

Published Date

Open AccessOriginal

First Online: 

20 January 2017

DOI: 10.1007/s00107-016-1148-5

Cite this article as: 

Bahari, S.A., Grigsby, W. & Krause, A. Eur. J. Wood Prod. (2017). doi:10.1007/s00107-016-1148-5

Author

Shahril Anuar BahariEmail author

Warren Grigsby

Abstract

Polyvinyl chloride (PVC) was mixed with bamboo (Bambusa vulgaris) particle and additives by using PVC composite manufacturing system including initial dry blending with hot-cool mixing, followed by granulation via counter-rotating extrusion, and then consolidation by compression moulding to produce compression moulded board (CMB). The effects of different bamboo particle size (75 µm and 1 mm), bamboo particle loading (25 and 50% loading ratio), and differing processing lubricants content level (compositions 1 and 2) on the thermal stability of the composites were determined. Results show no significant trends in glass transition temperature (Tg) between dry blends, granules, and CMB, and between B. vulgaris particle loading at the respective processing steps. For samples with higher lubricant contents, the PVC Tg was observed to decrease up to 5 °C, possibly due to the reduced melt viscosity. The thermal decomposition temperature at 5% mass loss (T−5%) appeared to decrease from dry blend to CMB due to sample degradation on further processing at higher temperatures. The use of 50% B. vulgaris particle loading also reduced the T−5% values, assignable to bamboo particle degradation caused by the high processing temperatures. For oxidative induction time (OIT) testing, only granules and CMB from pure PVC composites system showed measurable oxidative times compared with OIT profiles of PVC/B. vulgaris composites system, suggestive of comparatively stabilized thermoplastic composites. This revealed that processing with bamboo particles does not contribute to degradation of PVC composites.

Electronic supplementary material

The online version of this article (doi:10.1007/s00107-016-1148-5) contains supplementary material, which is available to authorized users.

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Modelling mechanical properties of spruce and Douglas fir timber by means of X-ray and grain angle measurements for strength grading purpose

Published Date

Original

First Online: 

21 January 2017

DOI: 10.1007/s00107-016-1149-4

Cite this article as: 

Viguier, J., Bourreau, D., Bocquet, JF. et al. Eur. J. Wood Prod. (2017). doi:10.1007/s00107-016-1149-4

Author

• Joffrey ViguierEmail author
• Damien Bourreau
• Jean-François Bocquet
• Guillaume Pot
• Laurent Bléron
• Jean-Denis Lanvin

Abstract

This study proposes a model using data from a scanner (X-ray and grain angle measurements) to perform strength grading. The research also includes global measurements of modulus of elasticity (obtained by vibrations and ultrasound methods), static bending stiffness and bending strength of 805 boards of Douglas fir and 437 boards of spruce. This model can be used in an industrial context since it requires low computational time. The results of this study show that the developed model gives better results than the global non-destructive measurements of the elastic modulus commonly used in the industry. It also shows that this improvement is particularly higher in the case of Douglas fir than for spruce. The comparison has been made on both the quality of the mechanical properties assessment and on the improvement of the grading process according to the European standards by using different index.

List of symbols

l

Length of the board

t

Thickness of the board

h

Height of the board

f

First natural frequency under longitudinal vibration

tsound$t_{sound}$

Travel time of the ultrasonic wave

ρ$\rho$

Board average density

G

Grey level of X-Ray Images

aρ,$a_{\rho }$ bρ$b_{\rho }$

Linear calibration coefficients of local density measurement

ρcw,${\rho }_{cw}$ ρknot${\rho }_{knot}$

Clear wood and knot density

f1,$f_1$ f2$f_2$

Parameters of the KDR calculation

KDR

Knot depth ratio: ratio between the knot’s thickness and the thickness of the board

θ$\theta$

Projection of the grain angle on the surface of the board

H(θ)$H\theta$

Function linking mechanical properties and grain angle

(EI)eff$EI{}_{eff}$

Effective bending stiffness

x, y

Local coordinates in length and height of the board

E(x, y)

Local modulus of elasticity calc. on basis of measured singularities

Em,g$E_{mg}$

Global MOE assessed by static bending with a span of 18 times the height of the board

Esound$E_{sound}$

MOE calc. on basis of the speed of an ultrasonic wave

Evib$E_{vib}$

MOE calc. on basis of the first natural frequency under longitudinal vibration

Emodel$E_{model}$

MOE calc. on basis of the proposed model for the same span as the actual static test

IPMOEmodel$IPMO{E}_{model}$

Indicating property of the MOE calc. on basis of the proposed model for the full-length of the board

σm${\sigma }_m$

Experimental bending strength with a span of 18 times the height of the board

σmodel${\sigma }_{model}$

Bending strength calc. on basis of the proposed model for the same span as the actual static test

IPMORmodel$IPMO{R}_{model}$

Indicating property of the MOR calc. on basis of the proposed model for the full-length of the board

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http://link.springer.com/article/10.1007/s00107-016-1149-4