Michael Watt
Scion, Forest Industry Informatics, Department Member
Research Interests:
Research Interests: Forestry, Forest Ecology And Management, Plant Cell Walls, Density, Forest Ecology, and 18 moreBiological Sciences, Fiber, Environmental Sciences, Wood, STEM, Planting, Growth rings, Length, Dimension, Genotype, Wood properties, Stand Density, Elastic Modulus, Wood Density, Cell Wall, Genotypes, Modulus of Elasticity, and Pinus radiata
Background: Mechanical bending stress due to tree sway in strong winds and water stress during drought are thought to contribute to the formation of resin pockets, but it is unclear if these are linked and whether the initiation of resin... more
Background: Mechanical bending stress due to tree sway in strong winds and water stress during drought are thought to contribute to the formation of resin pockets, but it is unclear if these are linked and whether the initiation of resin pockets is influenced by the water status of the trees at the time of stem bending. Methods: The effect of stem bending on the formation of resin pockets was evaluated under various soil moisture conditions. The stems of 12-year-old radiata pine (Pinus radiata D.Don) trees were bent mechanically in spring or summer when the soil was water deficient, and in summer after rehydration. After the completion of the growth season, a selected sample of trees was felled and stem discs were assessed for the presence of resin pockets, using disc photos and image analysis. All stem bending treatments were compared with control trees. Results: Stem bending in spring or summer was found to increase the number of Type 1 resin pockets, but had no effect on the numb...
Research Interests:
Research Interests:
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... more
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 the environmental conditions that control the incidence of these defects. In this study we collected data from 15 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 each tree into 50 mm sections. Each of these sections was then imaged and resin pockets were identified and allocated to a type, height and year of occurrence. Using these data, the objectives of this study were to (i) determine whether there is a significant relationship between the incidence of ...
Research Interests:
Research Interests:
ABSTRACT Kriticos DJ,Watt MS, Potter KJB, Manning LK,Alexander NS &Tallent-Halsell N (2011). Managing invasive weeds under climate change: considering the current and potential future distribution of Buddleja davidii. Weed... more
ABSTRACT Kriticos DJ,Watt MS, Potter KJB, Manning LK,Alexander NS &Tallent-Halsell N (2011). Managing invasive weeds under climate change: considering the current and potential future distribution of Buddleja davidii. Weed Research 51, 85–96.SummaryBuddleja davidii is both a prized garden ornamental and an invasive shrub that rapidly colonises disturbed ground. Originally from China, B. davidii has been widely distributed by horticulturalists and has subsequently invaded much of Europe and New Zealand, and to a lesser degree the Americas and Australia. The present and future climate suitability for B. davidii was assessed using a process-oriented climate suitability model. There appears to be a considerable scope for further invasion, with the most suitable areas occurring adjacent to existing naturalised populations in the north-eastern United States, north-eastern Europe, south-eastern Australia and south-eastern New Zealand. Under future climates, the potential distribution and climate suitability for B. davidii increases most noticeably in the northern United States and southern Canada, northern and eastern Europe, and to a lesser extent in the south-western part of the South Island of New Zealand. Elsewhere, there are projected poleward range shifts (South America) or range contractions out of subtropical areas (Africa and Australia). Climate-based potential distribution models can help adapt weed management programmes to expected climate changes by: (i) classifying areas for the different types of weed management, (ii) supporting strategic control initiatives to prevent the spread of a weed, (iii) informing the reallocation of resources away from controlling a weed where climate suitability is expected to diminish in the future and (iv) identifying opportunities for relatively inexpensive preventative management to be applied to minimise future weed impacts.