A 13C NMR study of decomposing logging residues in an Australian hoop pine plantation

Purpose

Residue retention is important for nutrient and water economy in subtropical plantation forests. We examined decomposing hoop pine (Araucaria cunninghamii Ait. Ex D. Don) residues—foliage, branches, and stem wood—to determine the changes in structural chemistry that occur during decomposition.

Materials and methods

Residues were incubated in situ using 0.05 m² microplots. We used solid-state ¹³C nuclear magnetic resonance (NMR) spectroscopy to determine the structural composition of harvest residues in the first 24 months of decomposition.

Results and discussion

The spectral data for branch and stem residues were generally similar to one another and showed few changes during decomposition. The lignin content of branch and foliage residues decreased during decomposition. When residues were mixed together during decomposition, the O-alkyl fraction of foliage decreased initially then increased up to 24 months, while the alkyl carbon (C) fraction exhibited the opposite pattern. The decomposition of woody hoop pine residues (branch and stem wood) is surprisingly uniform across the major C forms elucidated with ¹³C NMR, with little evidence of preferential decomposition. When mixed with branch and stem materials, foliage residues showed significant short- and long-term compositional changes. This synergistic effect may be due to the C/N ratio of the treatments and the structure of the microbial decomposer community.

Conclusions

Twenty-four months of decomposition of hoop pine residues did not result in substantial accumulation of recalcitrant C forms, suggesting that they may not contribute to long-term C sequestration.     

Pancreatic endocrinopathies in ferrets.

Pancreatic endocrinopathies, especially insulinomas, are a common finding in ferrets. Surgical resection remains the treatment of choice for insulinomas because it can provide longer disease-free intervals and survival times. Because of the high rate of metastasis, owners should be advised that treatment is rarely curative and is aimed at controlling the clinical signs of hypoglycemia by stopping or slowing the progression of the insulinoma. Although less common, diabetes mellitus can occur in ferrets, but is often a postsurgical sequela to insulinoma resection. Current advancements in diabetes management can be applied to ferrets with diabetes mellitus.     

Commercial embryo-transfers in cattle

Eighty-six cows and 46 heifers were operated on tosurgically recover embryos in a 5-month embryo-transfer season. The work was done for Southern Breeders Ltd, at Wairaki Station in Southland.

The programme was commercially successful. It resulted in 867 pregnant recipients at 90 days with an average of 4.23 pregnancies per donor operation.     

Online analysis of volatile organic compound emissions from Sitka spruce (Picea sitchensis)

Volatile organic compound (VOC) emissions from Sitka spruce (Picea sitchensis Bong.) growing in a range of controlled light and temperature regimes were monitored online with a proton transfer reaction-mass spectrometer (PTR-MS) operating at a temporal resolution of approximately 1 min. Isoprene emissions accounted for an average of more than 70% of measured VOCs and up to 3.5% of assimilated carbon. Emission rates (E) for isoprene correlated closely with photosynthetic photon flux (PPF) and temperature, showing saturation at a PPF of between 300 and 400 micromol m(-2) s(-1) and a maximum between 35 and 38 degrees C. Under standard conditions of 30 degrees C and 1000 micromol m(-2) s(-1) PPF, the mean isoprene E was 13 microg gdm(-1) h(-1), considerably higher than previously observed in this species. Mean E for acetaldehyde, methanol and monoterpenes at 30 degrees C were 0.37, 0.78 and 2.97 microg gdm(-1) h(-1), respectively. In response to a sudden light to dark transition, isoprene E decreased exponentially by > 98% over about 3 h; however, during the first 7 min, this otherwise steady decay was temporarily but immediately depressed to approximately 40% of the pre-darkness rate, before rallying during the following 7 min to rejoin the general downward trajectory of the exponential decay. The sudden sharp fall in isoprene E was mirrored by a burst in acetaldehyde E. The acetaldehyde E maximum coincided with the isoprene E minimum (7 min post-illumination), and ceased when isoprene emissions resumed their exponential decay. The causes of, and linkages between, these phenomena were investigated.     

Private native forest policies in New South Wales,Queensland, Victoria and Tasmania

Private native forests in Australia perform a dual production and conservation role, providing an important source of timber, and complementing formal conservation reserves. A comparison of policies for private native forests in New South Wales, Queensland, Victoria and Tasmania illustrates the scope for timber harvesting, the provision for environmental values, and initiatives for responsible and sustainable forest management. The sustainable management of Australia’s forests requires initiatives by both government and landowners to accommodate changes in community attitudes, new management strategies, integrated catchment management principles and both commercial and non-commercial opportunities for forest use. Of all of the Australian states, New South Wales has the most restrictive laws in terms of forest management and harvesting. Queensland and Victorian legislation have a more commercial focus, while Tasmania has a balance of both environmental and commercial objectives. The duty of care for private native forests is a responsibility that falls to the landholder, and while this should be enforced by legislation, the private provision of community benefits requires both recognition and reward. The presence or absence of incentives potentially determines the effectiveness of forest codes of practice.