TIMBER LOSSES CAUSED BY TERMITES,DECAY AND FIRE IN AN ALPINE FOREST IN NEW SOUTH WALES

A rating system for the assessment of damage to forest trees by termites, decay and fire is described.

Timber and royalty losses were assessed during harvest cuts of alpine ash (E. delegatensis R. T. Baker) and mountain gum (E. dalrympleana Maiden) in seven compartments in Bago State Forest, New South Wales.

In one compartment, part of which was a virgin stand of alpine ash, the combined losses due to these agencies were assessed at £37/13/- per acre, of which £1/15/- was due to downgrading merchantable logs, £23/12/- due to rejection of logs because of defect and £12/6/- per acre due to losses in trees which were ringbarked because of excessive defect. The total royalty return in this compartment was £71 per acre. These trees were from 60 to 150 years old when cut.

In a compartment previously treated by logging and ring-barking, and protected from fire from 1917 onwards, the losses were £6/5/- per acre, of which £5 per acre was contained in overmature seed trees. The royalty return in this compartment was £34 per acre from trees, 90 per cent of which were less than 70 years old when cut.

The losses were due mainly to termites Porotermes adamsoni (Froggatt) which caused up to 80 per cent of the damage, and to decay which caused 13 to 36 per cent. The actual loss due to damage by fire was less than 5 per cent of all losses; but fire was the cause of most scars, through which fungi and termites gained entry.

Between 80 and 91 per cent of the loss in each compartment was contained in large trees 90–150 years old.     

Reinfestation of Eucalyptus marginata ground coppice by jarrah leafminer after scorch by autumn or spring fires

Population densities of jarrah leafminer Perthida glyphopa in adjoining areas of jarrah Eucalyptus marginata forest in southwest Western Australia were monitored before and after autumn and spring fires, then compared to examine the effect of fire season and intensity. Densities of leafminer were reduced in tree canopies and on ground coppice after autumn fire scorched the host canopies. Densities of larval mines on ground coppice increased by the second spring after an autumn fire. Numbers of mines on leaves returned to levels indistinguishable from pre-fire values by the second autumn after fire. Leafminer populations on ground coppice appeared unaffected by a spring fire. Mechanisms that may account for observed differences between the effects of spring and autumn fires are discussed. Managed fires are not considered a practical tool for control of leafminer populations.     

Extreme wildfire behaviour in 3-year-old fuels in a Western Australian mixed Eucalyptus forest

This paper describes the behaviour of an intense wildfire which burnt through three-year-old fuels in open forest of jarrah (Eucalyptus marginata), marri (E. calophylla) and karri (E. diversicolor) near Manjimup, W.A. The fire occurred during very dry fuel conditions which resulted from record high air temperatures (maximum 43.5°C) following a rainless period of twenty eight days. Fire danger at the time was Extreme, with a peak McArthur Forest Fire Danger Index of 65. The fire crowned extensively in mixed-aged jarrah/marri stands, and it is proposed that crown fire initiation was facilitated by the substantial component of sapling and pole-sized regrowth which provided a vertically continuous fuel structure. Concentrated spotting occurred up to 2km downwind of the fire, and an isolated spot fire developed 8km away. During an initial run under north-westerly winds the fire travelled 2.2km with an average forward rate of spread of 1300m/h, which is somewhat faster than predicted by either the Western Australian Forest Fire Behaviour Tables or the McArthur Forest Fire Danger Meter. The relatively low fuel loads in the area appear to have assisted in the rapid containment of the fire once burning conditions moderated.     

Crown Recovery of Eucalyptus dives Following Wildfire

The restoration of crowns of 5–7 m tall trees of E. dives of coppice origin was studied after a wildfire on October 1, 1971, near Captains Flat, N.S.W. Unburned plants were compared with those which had their crowns completely scorched but not burned and those which had their leaves completely burned off by crown fire. All trees survived. Approximately 50 per cent of the height of crown-burned trees was killed and 30 per cent in the case of crown-scorched trees. While these results were significantly different most measurements of crown recovery were similar for these two classes of fire-affected plants. Leaf weight was restored within 8 months of the fire. The clumped pattern of epicormic shoots emergent along surviving trunks soon after the fire was replaced by that of the normal branching pattern less than three years later.     

Coleoptera in litter of dry sclerophyll eucalypt forest and the effects of low-intensity prescribed fire on their activity and composition in west-central Victoria

Surface-active Coleoptera (beetles) were monitored in dry sclerophyll mixed eucalypt forest of west-central Victoria near Daylesford, and the effects of a one-off low-intensity prescribed fire applied during spring (15 October 1985) or autumn (25 March 1987) were assessed on families and species between 19 March 1985 and 28 February 1989. The study was based on 27 550 adult specimens, ranging in length from 0.5 mm to 22.0 mm and representing 30 families and 109 species, of which 78 species (71.6%) are undescribed. The most commonly trapped ‘major’ families were the Staphylinidae (predominantly predators), followed by the Nitidulidae and Leiodidae (both decomposers/fungus feeders). The specimens were contained in 3 140 pitfall trap samples taken from two sites burnt in spring, two sites burnt in autumn and one ‘control’ site, all adjacent to each other within an 80.5 ha study area. This is the first Australian study that has examined in detail the effects of prescribed fire on both families and species of the Coleoptera within litter of native forest.

A high level of stability in activity was evident among coleopteran populations over the 4-year study period when fire was absent. The same was observed at the two sites burnt in autumn (fire intensity = 176 kW m^?1). Both fires had no effect on family or species richness. However, the spring fire (256 kW m^?1) at one study site temporarily boosted activity of the ‘major’ family Staphylinidae after early autumn of the second post-fire year, and induced a short burst in activity of species Thalycrodes pulchrum (Nitidulidae) during the first post-fire winter, and among Leiodidae during the first postfire spring. At both spring-burnt sites, the pool of the 19 less commonly trapped ‘minor’ families incurred an immediate post-fire upsurge lasting until early summer 1986. As these positive responses at the spring-burnt sites were associated with a 4.41 ha^?1 lower fine fuel load (humus, litter, twigs of < 6mm diameter) during the first post-fire year compared with the autumn-burnt sites, it is possible that they reflect enhanced trapping efficiency and not increased population levels. Until this question is resolved, it appears preferable to apply any necessary one-off prescribed fire for reducing fuel loads on the forest floor during autumn rather than spring to minimise possible short-term impacts on surface-active Coleoptera.     

Tree hollow development in wet and dry sclerophyll eucalypt forest in south-east Queensland,Australia

Tree hollow development was studied in Eucalyptus pilularis (blackbutt) and Eucalyptus microcorys (tallowwood) in wet sclerophyll forests, and Eucalyptus signata (scribbly gum) in dry sclerophyll forest in south-east Queensland, Australia. In all three tree species hollow development appeared to be primarily initiated by fungal infection entering trees through dead branches and/or branch stubs rather than from fire scars. The process of hollow development appeared to commence when the trees were around 100 years old.

The size and abundance of hollows increased with the size and age of the tree but there were apparent differences between species. Hollows were found in the majority (>50%) of E. pilularis trees above 100 cm dbh. By contrast most E. microcorys and E. signata larger than 80 cm dbh had hollows. There was a similar difference between species in the numbers of hollows present in trees of different size. E. pilularis trees 100–110 cm dbh had two hollows per tree but this number were present in much smaller E. microcorys or E. signata trees. The rate of growth of E. pilularis is faster than either E. microcorys or E. signata and the rate of hollow formation appears to be dependent on the growth rate of the species. This suggests that hollows begin to develop after comparable times in the different species although the time taken for large hollow development differs between the species.

The analyses suggest that the smallest arboreal marsupials and hollow dependent birds could recolonise regrowth E. pilularis trees after about 165 years but hollows suitable for larger animals would not be available for around 210 years. This time frame would be longer for slower growing species of trees. Some of the implications of this work in connection with management practices that aim to ensure the maintenance of hollow-dependent fauna in these forests are discussed.     

Frost tolerance of six seed orchards of Acacia mearnsii (black wattle) and the effect of developmental stage and tree size on frost hardiness

Frost damage is the most important abiotic risk in Acacia mearnsii (black wattle) plantations in South Africa. Current A. mearnsii planting stock cannot tolerate temperatures below ?4°C, and therefore there is an urgent need to develop frost-tolerant seed. This study investigated the frost hardiness of seedlots from six South African A. mearnsii seed orchards located at altitudes of 1120–1458 m asl and latitudes of 26.7–29.8°S that were established with cold-hardy Australian provenances and/or local landraces from cold sites. Frost damage was assessed in four field trials established on two different dates in 2015. Three sites experienced extensive frost events, with frequency and intensity varying among sites. Minimum temperatures ranged from ?6.4°C to ?7.7°C across sites. The seedlot from the coldest, highest altitude orchard showed superior frost hardiness to other seedlots from lower altitude and warmer orchards of similar genetic origin. Thus, site climatic characteristics are important for the development of cold hardiness in A. mearnsii seed orchards. Frost hardiness in young A. mearnsii trees was significantly related to age and tree size. At four months of age, trees were highly susceptible to frost damage irrespective of tree size and orchard origin (60–71% frosted trees). Frost hardiness increased with age and was very high at c. nine months across orchards (1–8% frosted trees at one site and 0–2% at another site). At nine months, although the extent of frost damage was low, this was inversely related to tree size. The percentage of trees that recovered from frost damage also increased with age of frost damage, this being 21% at the site frosted at four months of age and 65–67% at the sites frosted at nine months of age. Finally, there were no differences in tree growth at 14 months suggesting that, unlike cold hardiness, the differences in environment between the orchards did not affect the growth performance of the offspring.     

Ecology of the pest insect jarrah leaf miner (Lepidoptera) in relation to fire and timber harvesting in jarrah forest in Western Australia

During a period of 7 years we undertook 25 investigations of the ecology of jarrah leafminer Perthida glyphopa Common in relation to fire and logging of jarrah Eucalyptus marginata Donn ex Sm. forest. Prescribed low intensity fires in spring or timber harvesting did not consistently favour jarrah leafminer or disfavour parasitization of its mines. Moderate intensity fire in autumn reduced the density of jarrah leafminer for 18 months.

We integrate these findings with other relevant ecological and historical knowledge and theorize that scarcity of extensive scorching of codominant crowns in jarrah forest from the mid 1950s may have facilitated the spread of the outbreak. We recommend that more extensive autumn burning should be operationally introduced to both test the theory and subdue outbreaks of jarrah leafminer.     

Occurrence of potential nest trees and their use by birds in sclerophyll forest in north-east Tasmania

Breeding of hollow-nesting birds and the distribution and availability of tree hollows were investigated in an area of sclerophyll forest in north-eastern Tasmania. The occurrence of potential tree hollows was assessed from the ground and used as an index of actual hollows. Entrance size was categorized as small, medium or large corresponding to the differing requirements of the birds present on the site. Smaller hollows were more abundant than larger hollows. The distribution of hollows amongst trees was highly clumped. Diameter at breast height and the presence of a fire scar explained one-third of the variation in numbers of hollows per tree. Streamside and non-streamside areas did not differ in the number of hollows/tree or the sizes of hollows present. Thirty trees were found that were utilized as nest sites by striated pardalotes Pardalotus striatus, laughing kookaburras Dacelo novae- gaineae, green rosellas Platycercus caledonicus and yellow-tailed black cockatoo Calyptorhynchus funereus. In comparison with a representative sample of trees, nest trees were larger, had a greater number of potential hollows, a greater proportion of larger hollows and a greater proportion were fire scarred. Eucalyptus viminalis was used as a nest tree to a greater extent than expected from its relative abundance. Hollows appeared to be far in excess of the requirements of the birds present. Trees remaining in streamside reserves after logging would probably provide enough hollows to support the number of hollow-nesting birds present before logging. However, only 13% of striated pardalotes and none of the other species utilized streamside areas for nesting in the undisturbed forest.     

Growth response following variable espacement of 28-year-old Alpine Ash regeneration in New South Wales

Analysis of stand growth-response patterns have shown that small increases in sawlog volume resulted from thinning fast grown, fire regenerated alpine ash (Eucalyptus delegatensis R.T. Bak.) from below to a range of regular tree-spacings, at age 28 years. No significant correlation was found between basal area growth response and increased spacing for four treatments that ranged from 3.7 m to 7.3 m.

Rapid natural stocking-attrition occurred in both thinned and unthinned stands during the 31 post-thinning years of measurement. Maximum density diagrams indicated that these alpine ash stands were fully-stocked at lower densities than have been recorded for many other forest species. As a consequence of the propensity to self-thin, little additional stand growth was gained from the thinning treatments. The 150 trees ha^?1 with the largest diameters from all thinned stands averaged a basal area increase of only 0.59 mha^?1 over the 31 year period of measurement (<0.2 mha^?1 yr^?1), when compared with the equivalent stratum from an unthinned stand.

However, the small average nett growth response to spacing was not distributed evenly across the largest 150 trees ha^?1 dbhob. The 50 largest diameter trees ha^?1 in spaced stands showed a significant (α = 0.05) positive response, the trees ranked 51 to 100 showed no significant response and those trees ranked 101 to 150 showed a significant (α = 0.05) negative response when compared with the corresponding strata in the unthinned stand, over the same period.

Thus the overall result of stand spacing on the largest 150 trees ha^?1 was a widening of the stand diameter distribution and a small overall gain in the merchantable volume. For sites of higher quality, the basal area response was larger and predominantly accrued to the largest 50 trees ha^?1.     

NEW SOIL CONSERVATION ACT IN VICTORIA

The breeding programme at Traralgon aims to improve Eucalyptus regnans F. v. M. as a forest tree by increasing the rate of growth, improving wood quality, and increasing resistance to damage by fire. Improvement may be accomplished in three ways:—(1) provenance trials (to determine the best place to collect seed for afforestation in a given location), (2) selection of individual trees within the chosen provenance, and (3) hybrids with species with greater resistance to fire and the ability to grow on poor sites. The major part of the work has been the provenance trials which show continuous genetic variation with altitude on the south eastern side of Mount Erica, Victoria.

Seed for the trials was collected in October 1959 from 68 trees on Mount Erica. with an average of 10 trees at each of seven altitudes from 1200 feet to 3250 feet. Studies were made of capsule size, germination, cotyledon area, and growth of seedlings in the nursery. Sixty-four open pollinated progenies were planted in a cubic lattice design in the Strzelecki Ranges at 1650 feet, and some smaller trials were planted at other places. Field measurements at two years of age and again at three years confirmed the trend shown in the nursery that seedlings from higher altitudes grew more slowly. Leaf shape also varied with altitude but survival of seedlings did not. A study of the relation of nursery measurements to field measurements showed promise of a technique for culling the slowest growing progenies in the nursery without the need for field planting all the progenies.

An examination of growth rates of progenies from a given altitude showed that large dominant trees rarely produced the fastest growing seedlings, consequently trees selected for breeding should not be simply the largest individuals but rather the parents which give the best progeny in nursery and field trials.

Experiments were commenced on the value for forestry of hybrids of E. regnans and some observations were made on seed production.     

The Use of Lure Trees for the Detection of Sirex noctilio in the Field

Sawn timber losses due to degrade were investigated in a 28 year-old stand of radiata pine (Pinus radiata D.Don) subjected to a series of experimental fires covering a wide range of intensities. The effect of the burning treatment on radial growth rate and density characteristics was also studied and augmented by 44 year old material of the same species which had been burnt in a wild fire. These wood characteristics were also investigated in 17 year-old trees of maritime pine (P. pinaster Aiton).

The experimental fires caused a reduction of 0.4 per cent of the total possible sawn volume. There was no effect on growth rate and only a slight reduction in density in the immediate post-fire year. The accumulation of traumatic resin is discussed.     

Thinning Pinus radiata plantation by operator selection: 1. Effects on the residual forest

Field trials were undertaken in Pinus radiata plantation, in order to compare thinning where the harvesting machine operator selects the trees to be thinned without prior tree marking, with conventional tree-marked thinning, in terms of stand and tree parameters such as residual stocking and spacing, basal area, mean tree diameter, and frequency of damaged trees. These trials included first and second thinning on high and low site quality and two trials at operational scale. On the whole, operators thinned to the same stand density and tree diameter distribution as tree-marked thinning in comparable stands. The removal of undesirable trees was generally as good as in tree-marked thinning. In two trials operator selected thinning resulted in a better quality residual stand than tree-marked thinning. Trials at the operational level also indicate practicalities of two types of guidelines for operator selection thinning: a diameter limit; and spacing of residual trees.     

The influence of the jarrah leafminer Perthida glyphopa Common (Lepidoptera: Incurvariidae) and prescribed burning on the girth increment of jarrah Eucalyptus marginata Donn ex Smith

Girth increment in jarrah trees, E. marginata, both resistant and susceptible to the jarrah leafminer, P. glyphopa, was measured at 3 sites between 1971 and 1986 and at another site between 1971 and 1981. Significant annual losses of girth increment were detected in the susceptible trees damaged by the leafminer before and during the time of observation. In trees observed through the development of heavy infestation, significant girth increment losses occurred some 5 years after the damage began. Over the period of observation the mean losses of girth increment in the susceptible trees ranged from 44 to 70%.

Rainfall in both current and preceding years had a significant effect on the girth increment in all trees, but varied between sites. At the drier sites both resistant and susceptible trees responded significantly only to the current year's rainfall, while those at the wetter sites were significantly influenced by rainfall of the previous year. In the susceptible trees this effect was overridden by the influence of damage by the leafminer. Girth increment in both resistant and susceptible trees increased for 1 year after 4 out of 5 ground fires in spring that occurred during the time of observation.     

THE KNOTTY CORE OF EUCALYPTS

Investigations were carried out between 1939 and 1942 in South Australia to determine the amount and distribution of moisture within the trunks of Monterey pine trees (P. radiata Don) and to study the differences from tree to tree. Between 1946 and 1948, additional but less extensive investigations were conducted in the Australian Capital Territory.

Large variations occur within each tree. The vertical distribution of water shows several distinct trends: in some trees the moisture content decreases from the base to a minimum and then increases again towards the top, in others it increases progressively up the tree, while in other trees it decreases progressively with height. The heartwood is a dry region with a moisture content of approximately 45 per cent. The moisture content of the sapwood varies throughout the tree both vertically and laterally.

Big differences in moisture content occur from tree to tree. The wood of young trees is much moister than that of old trees and the moisture content of the trees of fast-growing stands is higher than that of trees of the same age growing on poorer sites. In some stands the wood of dominant trees is moister than that of the suppressed. Interesting seasonal changes occur in the moisture content of the trees, those studied at Mt. Burr containing more water in spring than in autumn.     

Management of compaction during harvest of Pinus plantations in Queensland: II. Preliminary evaluation of compaction effects on productivity

Two retrospective studies were conducted in the coarse-textured, coastal lowland soils of south-eastern Queensland to provide a preliminary assessment of compaction affects on the productivity of Pinus plantations.

In the first study, stem wood volume of a 9-year-old plantation established on a site used as a log dump during clearfell harvest of the first rotation was reduced by 40.3%. There was a clear link between persistent compaction, reduced root development and reduced wood production. Standard site preparation and cultivation operations used at the time of second rotation establishment did not ameliorate compaction damage. A number of operational measures are suggested for minimising the impact of log dumps on plantation productivity.

In the second study, dendro-chronological techniques were used to determine annual basal area increments (BAIs) of crop trees following thinning operations that resulted in rut compaction of various intensities. The methodology allowed both positive growth responses to thinning and adverse growth responses from compaction to be identified. BAI reduction was most prominent in larger trees adjacent to rut compaction exceeding 10 cm depth. For example, BAI of trees with a 27.5 cm under-bark diameter adjacent to ruts 15 and 35 cm deep was reduced by 17% and 29% respectively compared to increment of those adjacent to ruts 0 cm deep. The study provides support for proscribing rut compaction exceeding 10 cm in depth.     

CONTROL OF THE PINE BARK BEETLE (HYLASTES ATER) AT MT. BURR,SOUTH AUSTRALIA

This endemic beetle caused damage to the second rotation crop ot Pinus radiata at Mt. Burr, described by Boomsma and Adams (1943).

As an outcome of the investigations then made, a suggestion naturally arose that has since been tried, simplified, and regularly practised with entirely satisfactory results. Slash areas to be planted in winter are completely felled before mid-summer and burned in autumn.     

Effect of manual lymph drainage on removal of blood lactate after submaximal exercise

[Purpose] It has been well-established that exercise-induced muscle damage occurs following intense exercise. Massage is commonly used to manage muscle damage resulting from exercise. However the effect of massage after exercise is still not clear. The purpose of this study was to examine the effect of manual lymph drainage on muscle damage and on the removal of blood lactate following submaximal exercise (SE), as part of a solution to the challenging problem in sports medicine of muscular recovery after exercise. [Subjects and Methods] Eighteen healthy male students, with moderate exercise training, were randomly assigned to either receive manual lymph drainage (MLD) or serve as controls. Both groups were subjected to a graded exercise test, performed on a treadmill ergometer, to determine each subject’s individual anaerobic threshold (IAT). Seven days later, all subjects were made to run for 30 minutes on the same treadmill ergometer, at a running speed equivalent to the IAT. One group received MLD treatment, while the control subjects received no treatment. [Results] Following an increase immediately after exercise, lactic acid (LA) and lactate dehydrogenase (LDH) serum levels dropped rapidly and significantly at the end of MLD application and two hours after SE in the subjects receiving MLD. The course of creatine kinase (CK) and myoglobin levels was comparable, and with myoglobin showing a significant difference at 2 h after SE, and CK at 24 h after SE. [Conclusion] Manual lymph drainage after SE correlated with a more rapid fall in LA and of the muscular enzymes of LDH, CK and myoglobin, and may have resulted in an improvement in the regenerative processes elicted by structural damage to the muscle cells.Key words: Manual lymph drainage, Recovery, Submaximal exercise     

The susceptibility of the knee extensors to eccentric exercise‐induced muscle damage is not affected by leg dominance but by exercise order

The aims of this study were first to compare the response of dominant and non‐dominant legs to eccentric exercise and second, to examine whether there is an effect of exercise order on the magnitude of symptoms associated with intense eccentric protocols. Eighteen young men performed three sets of 30 maximal eccentric isokinetic (60° s^?1) contractions of the knee extensors (range of motion, ROM: 0°–100°, 0 = full extension) using either dominant or non‐dominant leg. They repeated a similar eccentric bout using the contralateral leg 6 weeks later. The sequence of leg's use was allocated to create equally balanced groups. Four indirect markers of muscle damage including subjective pain intensity, maximal isometric strength, muscle stiffness and plasma creatine kinase (CK) activity were measured before and 24 h after exercise. All markers changed significantly following the eccentric bout performed either by dominant or non‐dominant legs, but no significant difference was observed between legs. Interestingly, the comparison between the first and second eccentric bouts revealed that muscle soreness (?42%, P<0·001), CK activity (?62%, P<0·05) and strength loss (?54%, P<0·01) were significantly lower after the second bout. This study suggests that leg dominance does not influence the magnitude of exercise‐induced muscle damage and supports for the first time the existence of a contralateral protection against exercise‐induced muscle damage in the lower limbs.     

‘Dieback’ (chronic decline) of Eucalyptus viminalis on the Monaro is not new,unique or difficult to explain

Ross and Brack (2015) reported a widespread decline over the past decade in the health of Eucalyptus viminalis on the Monaro Tablelands in southern New South Wales. They were unable to attribute this to changes in management, lack of fire, or ‘declining levels of structural diversity’. They noted consistent infestation of trees by a native weevil and recommended further work on the role of climate and rainfall in ‘Monaro dieback’. However, chronic decline involving a wide range of arbivores has affected a wide range of eucalypts across Australia since European settlement, and is currently rampant in many areas of forest and woodland. Pasture improvement and/or exclusion of fire and grazing are the major causes of chronically declining health of eucalypts. The data presented by Ross and Brack (2015) provide some support for this conclusion and no contrary evidence.