@article {BF-4273, title = {Leaf growth and senescence rates of three pasture grasses and wheat}, journal = {Crop \& Pasture Science}, volume = {64}, year = {2013}, month = {10/2013}, pages = {660-672}, chapter = {660}, abstract = {A glasshouse study was conducted under ideal conditions to determine leaf appearance, elongation, and senescence rates along with life span and leaf length characteristics of four grass species: wheat (Triticum aestivum L.), brown back wallaby grass (Rytidosperma duttonianum (Cashmore) Connor and Edgar), phalaris (Phalaris aquatica L.), and annual ryegrass (Lolium rigidum Gaud.). This study provided a comprehensive characterisation of leaf turnover rates for the entire life cycle of these grasses, some of which are poorly characterised. Importantly, leaf senescence rate has been captured in the same conditions as the other leaf rates of the life cycle. Leaf position proved to be a significant explanatory variable in each of the leaf turnover rates. The relationships between leaf position and the components of leaf turnover were most commonly represented by non-linear models. Further studies may be necessary to validate these statistical models to field situations. However, this information will be useful to calibrate the senescence algorithms of plant growth models in agricultural decision support tools, which may then be applied to simulation studies including the assessment of grass curing for planning activities such as resource allocation, wildfire suppression, and execution of prescribed burning programs by fire management agencies.}, doi = {http://dx.doi.org/10.1071/CP13178}, url = {http://www.publish.csiro.au/paper/CP13178.htm}, author = {Helen G Daily and Peter A Lane and Shaun N Lisson and Kerry L Bridle and Stuart AJ Anderson and Corkrey, Ross} } @article {BF-2787, title = {Does low-intensity surface fire increase water- and nutrient-availability to overstorey Eucalyptus gomphocephala?}, journal = {Plant and Soil}, year = {2011}, abstract = {The objective of this study was to investigate how the management practices of prescribed fire and understorey vegetation removal affect water and nutrient relations of old, yet prematurely declining Eucalyptus gomphocephala. Long unburnt sites were established in Yalgorup National Park, Western Australia, adjacent to frequently burnt state forest sites. Trees were allocated to vegetation clearing, prescribed fire or no prescribed fire treatments. Prescribed fire was achieved in only one long unburnt national park site so that the results were pseudoreplicated but analysed accordingly. Soil chemistry, plant nutrient availability and tree foliar carbon and nitrogen isotope ratio and nutrient concentration were investigated. No effects of vegetation clearing were found. Prescribed fire sites were associated with sky exposure and bare ground whereas no prescribed fire sites were associated with shrub and litter cover and litter depth. Foliar carbon isotope ratios were significantly more negative in prescribed fire, relative to no prescribed fire, treatments on long unburnt sites. Soil exchangeable Zn and Mn and plant available (estimated by charged resin beads) Mg were higher on prescribed fire, relative to no prescribed fire, long unburnt sites. Seedling bioassays indicated elevated P and Cu availability on prescribed fire, relative to no prescribed fire, treatments. In overstorey E. gomphocephala, foliar N levels were elevated (but not to excessive levels), and there was a trend toward elevated foliar Mn, in prescribed fire relative to no prescribed fire treatments on long unburnt sites. In the context of our large-scale pseudoreplicated case study, prescribed fire provided a pulse of water and N, (with some indications towards provision of elevated Mn, Cu and Mg) availability to E. gomphocephala in decline on sites with a history of a long absence of fire that may in part underpin observations of elevated tree health on sites that have a history of relatively frequent fire. }, doi = {10.1007/s11104-011-0862-3}, author = {Close, DC and Davidson, N. J. and Swanborough, Perry W. and Corkrey, Ross} } @article {BF-2424, title = {Can climate at the seed-source predict the success of eucalypts planted on sites that have been grazed for over 100 years?}, journal = {Forest Ecology and Management}, volume = {259}, year = {2010}, month = {02/2010}, pages = {1025 - 1032}, abstract = {Many regions of southern Australia exposed to broad-acre grazing are denuded of trees. Re-establishing trees in these landscapes is important for both environmental and economic reasons. We investigated whether climate at the site of origin of the seed can inform species selection for tree establishment on ex-pasture sites within agricultural landscapes. We established trials at four sites in the sheep and cattle grazing region of the Midlands of Tasmania at: {\textquoteleft}Woodland Park{\textquoteright}; {\textquoteleft}Sorrel Springs{\textquoteright}; {\textquoteleft}Inverel{\textquoteright} and {\textquoteleft}Glen Morey{\textquoteright} farms (long-term average rainfalls of 584, 520, 520, and 479 mm, respectively). Eucalypt species were selected, based on high tolerance to frost and drought inferred from climate at the sites of origin and based on the limited scientific literature available, from across Tasmania and mainland Australia. We investigated the mortality, health and height growth of 18 eucalypt species three months, one and six years after planting. Climatic data from the site of origin of the seed of these species was used to group species into categories of mean annual temperature and mean annual rainfall at seed-source. Sensitivity of species to environment was investigated and compared using modified joint regression. At three planting sites, Woodland Park, Sorrel Springs (except health of the temperature category comparison at six years) and Inverel, we found significantly greater height and health one and six years after planting for local (Tasmanian) compared to non-local (Australian mainland) species, and for species where the site of origin of seed was categorised as low or medium mean annual temperature compared with those categorised as high mean annual temperature. There were no significant differences in mortality for these comparisons. At Glen Morey, height was significantly greater at six years after planting of local compared to non-local species and of species from low and medium mean annual temperature categories compared with the high mean annual temperature category. Mortality was significantly greater in local than non-local species six years after planting. Health was not significantly different for these comparisons. Differences in height, health or mortality of species categorised into mean annual rainfall at seed-source were largely non-significant at all sites one and six years after planting. A study of the sensitivity of species to environment of planting indicated that Tasmanian species were less sensitive than mainland species when height data was compared. When health data was compared, species with a site of origin of seed categorised as low rainfall were less sensitive to environment than species categorised as medium and high-mean rainfall. When mortality data was used significant differences were identified in the sensitivity of species to planting environment but this was not related to locality, mean annual temperature or rainfall at seed-source. Species that attained above average height and low mortality across three or more sites included Eucalyptus pulchella, Eucalyptus perineana (Tasmanian species), and Eucalyptus microcarpa, Eucalyptus benthamii and Eucalyptus melliodora (mainland species). Whilst temperature (and to a lesser extent rainfall) at seed-source is a good indicator of the success of tree establishment, high variability between sites points to the need to consider climate, browsing pressure and farm management at the paddock-scale when planning revegetation plantings. This has important implications for carbon sequestration plantings.}, doi = {10.1016/j.foreco.2009.12.010}, author = {Close, DC and Davidson, N. J. and Churchill, KC and Corkrey, Ross} }