NZJFS - Volume 41 (2011)

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  Acknowledgement to referees - Volume 41

  The Editors are most grateful to the following referees who reviewed manuscripts that were subsequently published in Volume 41 or were rejected during 2011.

  05/12/2011.
  ISSN 1179-5395. [502.6 KB].

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  New Zealand Journal of Forestry Science: past and present

  Falshaw, R., Gadgil, R. & Gadgil, P. D.
  

  Falshaw et al. (pp. 231-235) briefly review the first forty years of the New Zealand Journal of Forestry Science.

  05/12/2011.
  ISSN 1179-5395. [2.3 MB].

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  Meta-analysis of racial variation in Eucalyptus nitens and E. denticulata

  Hamilton, M. G., Dutkowski, G. W., Joyce, K. R., & Potts, B. M.
  

  Hamilton et al. (pp. 217-230) reviewed data from 85 southern hemisphere E. nitens/E. denticulata field trials to investigate racial (among population groups) genetic variation in growth, wood-property, tree-architecture, fitness and morphological/developmental traits. Significant differences among races were detected.

  02/12/2011. 217-230.
  ISSN 1179-5395. [1.3 MB].

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  Eucalyptus nitens (Deane & Maiden) Maiden is widely planted in temperate regions of the southern hemisphere, principally for pulpwood production. Eucalyptus denticulata I.O. Cook & P.Y. Ladiges was previously recognised as an informal variant of E. nitens and, accordingly, was included in many ‘E. nitens’ field trials. We reviewed data from 85 E. nitens/E. denticulata field trials, located in Australia, Chile, China, Italy, Lesotho, New Zealand, South Africa and Zimbabwe and ranging in age from less than one year to 14 years, to investigate racial (among population groups) genetic variation in growth, wood-property, tree-architecture, fitness and morphological / developmental traits. Meta-analyses were undertaken on these data to gauge the significance of differences among races across trials. Race × rainfall zone interaction was also investigated by categorising field trials as summer-rainfall, winter-rainfall or nursery-based. Race × rainfall zone interaction was significant for growth traits only. In general, Central Victorian E. nitens populations outperformed New South Wales E. nitens populations in winter-rainfall zones, but this ranking was reversed in summer-rainfall zones. On average, E. denticulata grew less rapidly than the best-performing E. nitens races, particularly in winter-rainfall zones. Differences among races were detected in basic density, a commercially important trait, but these differences were small in magnitude. Significant differences among races were also evident in branch size and stem form (straightness). Eucalyptus denticulata races had significantly thinner branches than all E. nitens races except Southern Central Victorian, and Central Victorian E. nitens races generally had the straightest stems. The small number of trials represented for most traits limited the power of meta-analyses but significant differences among races detected in our study are likely to represent consistent and robust differences across a broad range of environments.
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  Predicting the severity of Dothistroma needle blight on Pinus radiata under future climate in New Zealand

  Watt, M. S., Palmer, D. J., & Bulman, L. S.
  

  Watt et al. (pp. 207-215) predicted possible changes in severity of Dothistroma needle blight over the next eighty years using a range of climate scenarios. Their results suggest that climate change is likely to have a significant effect on severity of Dothistroma needle blight over the long term.

  01/12/2011. 207-215.
  ISSN 1179-5395. [706.6 KB].

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  Dothistroma needle blight is a very damaging foliar disease of Pinus species. An existing model for predicting spatial variation in Dothistroma needle blight severity was used to predict disease severity (S_sev) under current and future climate.

  Spatial predictions of S_sev under current climate varied widely throughout New Zealand. Values of S_sev were highest in moderately warm wet environments in the North Island and on the west coast of the South Island. In contrast, relatively low values of S_sev were predicted in drier eastern and southern regions of New Zealand.

  Changes in S_sev from current climate were predicted to be low to moderate under climates projected for 2040. However, over the longer term, to 2090, projected changes in S_sev, resulting from climate change, ranged from moderate to high. Over both projection periods, S_sev was predicted to decline in the North Island and increase within the South Island. Surfaces such as those presented here are a critical element for decision support systems that provide information on site suitability for plantation species under increasing rates of global warming.
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  Determining an optimal model for processing lidar data at the plot level: results for a Pinus radiata plantation in New South Wales, Australia

  Stone, C., Penman, T., & Turner, R.
  

  Stone et al. (pp. 191-205) collected airborne lidar and plot-based data from a radiata pine plantation in New South Wales, Australia. They extracted a series of area-based lidar metrics and these modelled against mean tree height, stem density, basal area and stand volume using various modelling techniques. The best models were used to produce prediction maps of these four inventory attributes. These results support the operational inclusion of airborne lidar data within P. radiata resource inventory systems.

  09/11/2011. 191-205.
  ISSN 1179-5395. [1.1 MB].

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  Small-footprint, discrete return airborne laser scanning (ALS or lidar) data is increasingly being used by forest managers to assist forest inventories. In this study, airborne lidar and plot-based data were collected from a 5 000 ha study site within Green Hills State Forest, a Pinus radiata D.Don plantation in southern New South Wales, Australia. A series of area-based lidar metrics were extracted and modelled against four inventory attributes (mean tree height, stem density, basal area and stand volume) obtained from 63 ground plots. For all response variables, regression tree models had the best model fit compared to Random Forest and Bayesian Model Averaging modelling techniques. The best regression tree models were based on the lidar metrics: the 5^th and 95^th height percentiles, minimum vegetation height, density of non-ground returns and a measure of spatial variation, the rumple index. All these metrics can be easily derived from the lidar data. The best regression tree models for each inventory attribute produced the following R² values: for mean tree height (m), R² = 0.94; stocking (trees ha^-1), R² = 0.85; basal area (m² ha^-1), R² = 0.81 and for stand volume, R² = 0.81 (m³ ha^-1) while the corresponding relative RMSEs were 5.8%, 23.4%, 15.5% and 22.3%, respectively. These models were then used to produce prediction maps over a 50 m grid across the 5 000 ha study site. Results from this study support the operational inclusion of airborne lidar data within P. radiata resource inventory systems.
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  Planted Forest Carbon Monitoring System - forest carbon model validation study for Pinus radiata

  Beets, P. N., Kimberley, M. O., Paul, T. S. H., & Garrett, L. G.
  

  Beets et al. (pp. 165-177) empirically validated the accuracy and precision of carbon stock and change estimates and predictions from the Forest Carbon Predictor model. Total carbon stock estimates at the inventory date and stock change projections over a 5 year interval are expected to average within 5% of actual values.

  08/11/2011. 177-189.
  ISSN 1179-5395. [1.8 MB].

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  A plot based inventory system in conjunction with models is being used to facilitate predictions of carbon stocks and changes in New Zealand’s planted forests. The models include the 300 Index Growth Model for Pinus radiata D.Don to predict stem gross and net volume under bark over a rotation using plot data, linked with a wood density model to convert stem volume to carbon, and C_Change to calculate carbon stocks annually in four pools - above-ground biomass, below-ground biomass, dead wood and litter. This linked suite of models is called the Forest Carbon Predictor version 3.

  This model validation paper aims to empirically determine the accuracy and precision of carbon stock and change estimates and predictions from the Forest Carbon Predictor, using independent above-ground biomass measurements acquired at permanent plots located in 39 stands throughout New Zealand and dead organic matter measurements from 14 stands. Model error was assessed using plot inventory data acquired in the same year that biomass measurements were made (model estimation error), and using plot measurements made nominally 5 years before or 5 years after the biomass measurement (model prediction error).

  Model bias and 95% confidence interval of the bias averaged -1.2% ± 2.6 m³ ha^-1 for stem volume, -0.8% ± 1.9 kg m^-3 for wood density, 3.7% ± 7.9 t ha^-1 for total carbon (excluding mineral soil carbon), -0.9% ± 5.6 t ha^-1 for above-ground biomass carbon, and 4.7% ± 12.6 t ha^-1 for dead organic matter. The model prediction error was similar to the model estimation error over growth projection intervals of ± 5 years. Total carbon stock estimates at the inventory date and stock change projections over a 5 year interval are expected to average within 5% of actual values.
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  Preliminary screening of herbicide mixes for the control of five major weed species on certified Pinus radiata plantations in New Zealand.

  Rolando, C. A., Gous, S. F., & Watt, M. S.
  

  Rolando et al. (pp. 165-177) conducted a pot trial to test for a combination of herbicides as potential replacements for hexazinone and terbuthylazine. Suitable alternatives needed to be effective against a wide range of weeds while having low phytotoxicity to Pinus radiata. The results indicated that haloxyfop, clopyralid, triclopyr and picloram are potential replacements for the control of fogg grass, pampas, broom and gorse during year one.

  04/11/2011. 165-175.
  ISSN 1179-5395. [739.5 KB].

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  The herbicides terbuthylazine and hexazinone are widely used by the New Zealand forest industry to control a range of weeds during first year vegetation management operations. These herbicides do not comply with certain eco-certification criteria and have been placed on a list of prohibited pesticides by the Forest Stewardship Council (FSC). Currently they cannot be used on FSC-certified land unless an approval is obtained. A pot trial was conducted to test for a combination of herbicides, not currently prohibited by FSC, that might have the potential to provide control of a wide range of weeds, including both broadleaves and grasses, with low phytotoxicity to Pinus radiata D.Don. Two groups of active ingredients were included in mixes used in the trial: (1) triclopyr, clopyralid and picloram for control of broadleaves; and (2) haloxyfop and quizalofop for control of grasses. Terbuthylazine was also included in the trial in the event that an approval is obtained for continued use there-of in New Zealand. We tested the herbicide combinations at 25%, 50%, 75% and 100% of recommended rates on six species: Pinus radiata, Cytisus scoparius L. (broom), Buddleja davidii Franchet (buddleja), Ulex europaeus L. (gorse), Holcus lanatus L. (fogg grass) and Cortaderia selloana (Schult) Asch. et Graeb. (pampas).

  The results indicated that potential replacements for hexazinone and terbuthylazine during year one for the control of fogg grass, pampas, broom and gorse are haloxyfop, clopyralid, triclopyr and picloram. Terbuthylazine used in combination with triclopyr and picloram was the only combination of herbicides tested that caused mortality of buddleja. The herbicide combinations and rates require further testing both in pot and field trials before robust recommendations for field application can be made.
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  Survival and growth to age 8 of four Populus maximowiczii × P. nigra clones in field trials on pastoral hill slopes in six climatic zones of New Zealand.

  McIvor, I. R., Hedderley, D. I., Hurst, S. E., & Fung, L. E.
  

  McIvor et al. (pp.151-163) trialled four experimental Populus maximowiczii × P. nigra clones in six different climatic zones. The results suggest that these clones are particularly suitable for colder sites subject to severe winter frosts and to warmer sites with regular rainfall, where their high rust resistance is an advantage. These clones also showed a high tolerance to wind. They are less suited to sites prone to salt spray and to summer drought.

  30/09/2011. 151-163.
  ISSN 1179-5395. [727.5 KB].

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  McIvor et al. (pp.151-163) trialled four experimental Populus maximowiczii × P. nigra clones in six different climatic zones. The results suggest that these clones are particularly suitable for colder sites subject to severe winter frosts and to warmer sites with regular rainfall, where their high rust resistance is an advantage. These clones also showed a high tolerance to wind. They are less suited to sites prone to salt spray and to summer drought.

  In New Zealand, poplars are commonly planted on moist, unstable pastoral hill country to combat soil erosion. Four Populus maximowiczii × P. nigra experimental clones, bred for soil stabilisation, were trialled on pastoral land in six different climatic zones. The experimental clones (identified as NZ5033, NZ5034, NZ5035, NZ5036) were planted together with six New Zealand-bred commercially available clones (four P. deltoides × P. nigra clones, either ‘Toa’ (P. × euramericana × P. yunnanensis) or ‘Kawa’ (P. deltoides × P. yunnanensis), and ‘Shinsei’ (P. nigra × P. maximowiczii)). The clones were planted as unrooted 3-m poles on open, generally sloping (and often broken) terrain. Replication was 5 or 10 poles per clone/site/year subclass. Survival, height and diameter at breast height (DBH) were measured six to eight years after establishment. Survival of the experimental clones was similar to that of the commercial clones. For height and DBH, NZ5034 was a superior clone, NZ5035 was an average clone, NZ5033 was an average to below-average clone, and NZ5036 was a below-average clone, compared with the commercial clones tested in the trials.

  The P. maximowiczii × P. nigra clones are considered particularly suitable for colder sites subject to severe winter frosts and to warmer sites with regular rainfall, where their high rust resistance is an advantage. They also showed a high tolerance to wind. They are less suited to sites prone to salt spray and to summer drought.
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  Characterisation of within-tree and within-ring resin-pocket density in Pinus radiata across an environmental range in New Zealand.

  Watt, M. S., Kimberley, M. O., Downes, G. M., Bruce, J., Jones, T., Ottenschlaeger, M., Brownlie, R., Xue, J., Leckie, A. C., & Smaill, S. J.
  

  Watt et al. (pp.141-150) found differences in the frequency and distribution of type-1 and type-2 resin pockets within Pinus radiata trees.

  22/08/2011. 141-150.
  ISSN 1179-5395. [933.2 KB].

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  Resin pockets are found in the xylem of conifers belonging to four main genera and can generally be classified into two types. Type 1 are radially narrow discontinuities in the wood while type 2 are radially flattened, contain less callus tissue, and are open to the external environment at early stages in their development. Although resin pockets are a major cause of degrade for appearance grade timber little is known about how the frequency of type-1 and type-2 resin pockets varies within trees and within rings.
  
  In this study, we collected data from 15- to 18-year-old Pinus radiata D.Don stands at four sites covering a wide environmental gradient. Resin pocket frequency was determined by cutting the lower 5 m of six trees at each site into 50 mm sections. Each of these sections was then imaged. Resin pockets were identified as type 1 or type 2 and the location of the resin pockets in three dimensions was recorded. Using these detailed measurements, the objectives of this study were to characterise: (i) three-dimensional variation in type-1 and type-2 resin pocket frequency within trees; and (ii) the position of type-1 and type-2 resin pockets within rings.
  
  The frequency of type-2 resin pockets was double that of type-1 resin pockets, and this ratio did not vary significantly between sites. Within trees, resin pocket density varied markedly in the radial but not the longitudinal or circumferential dimensions. At all four sites, variation in the radial dimension was characterised by an absence of resin pockets in the inner rings and fluctuating resin pocket densities in the outer rings. The age at which substantial resin pocket formation began ranged from 4 years on the fastest growing site to 8 years on the slowest growing site. On the driest sites, resin pocket incidence consistently peaked in the latter part of the growth ring in all trees, but on the windiest and wettest site the distribution was more irregular and varied between trees. The distribution of type-1 and type-2 resin pockets was highly segregated within the growth ring with mean positions occurring respectively at ca. the 30th and 80th percentile of the growth ring width.
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  Letter to the Editor.

  Burdon, R. D.
  

  Shoot dieback epidemics in Pinus radiata in New Zealand: is there an endophyte story?

  12/08/2011. 131-139.
  ISSN 1179-5395. [2.9 MB].

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