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.     

Mortality of Eucalyptus marginata (jarrah) and E. calophylla (marri) trees following stem injection: effects of herbicide,dose, season,and spacing of injections

Mortalities of Eucalyptus marginata Donn ex Smith (jarrah) and E. calophylla R.Br, (marri) trees injected with Roundup^TM (360 g glyphosate l^?1 ) or Tordon Timber Control^TM (50 g picloram l^?1 and 100 g triclopyr l^?1 ) (P+T) were determined at doses of 5 to 80 grams of active ingredient (g.a.i.) m^?2 of stem basal area for glyphosate, and 2 to 40 g.a.i. m^?2 for P+T. The effect of spacing of injections around the tree bole was examined. Seasonal variation in mortality was examined in relation to atmospheric vapour pressure deficit (v.p.d.) and soil water deficits.

Glyphosate was more effective in killing E. marginata trees, whereas P+T tended to be more effective in killing E. calophylla trees. The optimum doses of glyphosate and P+T for E. marginata trees were 20 g.a.i. m^?2 and 15 g.a.i. m^?2 respectively, and for E. calophylla 80 g.a.i. m^?2 and 15 g.a.i. m^?2 respectively. Spacing of injections around the circumference of the tree did not have a significant effect on the mortality of E. marginata trees injected with glyphosate. However, mortality of E. calophylla trees injected with P+T declined from 89% at 10–15 cm spacing to 70% at 25–50 cm spacing.

There were strong seasonal effects with both herbicides and in both species, with mortality higher (70 - 90 % mortality) in seasons other than summer (30 - 50 % mortality). For E. marginata trees injected with glyphosate, mortality declined linearly with increasing v.p.d., from 95% at a v.p.d. of 0.5 kPa, to 25% at 4.5 kPa. For E. calophylla trees injected with P+T, mortality declined linearly with increasing v.p.d., from 85% mortality at a v.p.d. of 0.5 kPa, to 50% at 3.0 kPa. Stem injection of both species should only be carried out when the vapour pressure deficit on the day prior to stem injection is less than 1.5 kPa.     

CORRESPONDENCE

The attack toy termites on indigenous eucalypt forests in Australia results in a serious loss of timber.

Porotermes adamsoni is the most serious pest of alpine forests in New South Wales, Tasmania, and Victoria; and two species of Coptotermes (C. acinaciformis and C. frenchi) are very serious pests of trees in coastal forests and savannah woodland areas.

Healthy trees in plantations of exotic pines are not attacked.

It is possible that the attack by P. adamsoni can be reduced considerably by a sound regeneration program involving the removal of veteran trees and good silvicultural treatment of all trees before they reach the veteran stage. Such programs are being carried out in Australia.

In contrast to P. adamsoni the damage to highly developed coastal eucalypt forests by the two Coptotermes spp. remains severe. Trees are often attacked well before they reach mill log size.

Studies of tile gallery systems of C. acinaciformis have shown that the termites from a colony within one living tree can attack other living trees up to a distance of 120 ft.

Population studies have shown that mature colonies of C. frenchi have a population of more than 400,000 termites, and those of C. acinaciformis over 770,000. The study of the temperature conditions in termite colonies situated in living trees has shown that the temperature within the “nursery” area is much higher than the ambient temperature.

The results obtained have provided a background for the control of colonies.     

Long term effects of hail damage on radiata pine

On 20 October, 1940, some 510 ha of 4 to 13 years-old Pinus radiata in the Ovens Plantation, near Myrtleford, Victoria, were damaged by a severe hail storm. When clearfelling began 20 years later it was found that the logs from the hail-damaged trees had defects.

Severe degrade of the timber was found in trees with open and occluded scars on the limbs and trunk or with death of the original tree top. Hail imprints on the bark often indicated the presence of separation of wood between growth rings. Other forms of degrade were cankers on the tree trunk, faulty knots, and accumulations of resin which caused staining when softened during seasoning. Sawn timber recovery from damaged logs was about 50% of that normally obtained from undamaged logs, and new defects sometimes appeared after milling.     

CROWN RATIO AND IRREGULAR STOCKING

Control of mistletoe, a cause of tree decline and death, was investigated in north-eastern Victoria because of reports that mistletoe infestations had increased in recent years. The potential of four herbicides to control mistletoe (Amyema spp.) by injection of the trunks of host eucalypts was evaluated. Eleven eucalypt species were injected in different months in 1984 and 1985 with solutions of the translocatable herbicides GARLON, LONTREL, ROUNDUP and VELPAR.

Evaluation of mistletoe control in conjunction with host health at 12 and 24 months after injection showed that mistletoes could be partially controlled on most species with certain herbicides. The best results were given by ROUNDUP (diluted 1:3 in water) or GARLON (1:4) injected at the rate of 1 mL per cut, with cuts spaced at 10 cm intervals around the lower trunk of the host tree. LONTREL and VELPAR gave unsatisfactory results, though they received only limited testing.

The particular herbicide and month of injection that gave the greatest percentage control of mistletoes with no or limited host mortality varied according to the eucalypt species, although the most effective months were commonly January and June. Smaller host trees (< 30 cm diameter) were significantly more susceptible to death following injection than larger trees.

This study has established that host injection with certain herbicides is a feasible and effective technique for reducing Amyema spp. populations on many eucalypt species. The results should be applicable to the 11 studied host eucalypt species infested with Amyema spp. growing elsewhere under similar conditions, but extrapolation to other species or genera (of host or mistletoe) would be inadvisable without further tests.     

An index combining volume and Pilodyn penetration to study stability and adaptability of Eucalyptus multi-species hybrids in Rio Grande do Sul,Brazil

This paper presents results from a study into the stability and adaptability of Eucalyptus multi-species hybrids in the state of Rio Grande do Sul, Brazil, using an index that includes volume growth and Pilodyn penetration. Clonal tests were established with 146 Eucalyptus clones from 34 different species and/or hybrids, in a randomised block design with 30 replications, and one plant per plot in four different sites. Diameter at breast height (dbh), tree total height (th), and Pilodyn penetration for indirect estimate of basic density were measured in trees at three years of age. An index (MAI_weight) combining mean annual volume increment and Pilodyn penetration was calculated. In the analysis of MAI_weight for each site, the best clones were from pure species (E. urophylla, E. grandis and E. saligna). In contrast, the evaluation of adaptability and stability between the four environments simultaneously showed that three-way cross and single cross hybrids ranked more highly: E. urophylla × (E. camaldulensis × E. grandis), E. grandis × (E. urophylla × E. grandis) and E. grandis × E. urophylla. This study demonstrates the importance of heterosis (hybrid vigour) to improving adaptability and stability. Genetic complementarity from crosses between different species was the principal process that produced the observed heterosis. While the pure species performed well in specific environments, the hybrids presented better broad adaptation to a range of environments. Breeding efforts should therefore account for these features when planning crosses and choosing sites for establishing trials.     

Influence of tree age and density on the above-ground natural durability of eucalypt species at Innisfail

An above-ground flat-panel test was conducted at Innisfail to determine the influence of tree age on natural durability against decay of heartwood of eucalypt species grown in low-rainfall areas. After nine years’ exposure, heartwood from trees aged 30–50 or 80+ years had similar natural durabilities in Eucalyptus sideroxylon, Corymbia spp., E. cladocalyx and E. occidentalis. However, except for E. cladocalyx, the heartwood from trees less than 25 years old was less durable than that from older trees for Corymbia spp., E. leucoxylon, E. occidentalis and E. sideroxylon. Density was a useful predictor of natural durability, especially in the lower range that differentiated wood in young trees. The importance of density within the more-mature tree age ranges of 30–50 years and 80+ years was unclear, perhaps showing that a threshold age for the production of mature heartwood had been reached. Comparisons, including with the yardstick species Pinus radiata, E. regnans, E. obliqua and E. camaldulensis, suggest that E. occidentalis could be assigned a class-2 above-ground natural durability rating in AS 5604, while the class-1 rating for E. astringens should be re-examined.     

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.     

Estimating the volume of Australian hardwoods using centroid sampling

Centroid sampling was tested on 18 sample trees of Flindersia brayleyana and 124 sample trees of five species of Eucalyptus all of which were measured in detail. Volumes of the main bole of each tree and of logs (length approx. 6 m) derived from each bole were estimated using both Huber's formula and centroid sampling. These estimates were compared with ‘true’ volume obtained by summing the volumes derived using Smalian's formula of all the measured short sections comprising the main bole and each log respectively.

The mean error of the centroid estimate of volume of the main bole was not significant for Eucalyptus sieberi and E. diversicolor and was less than that derived from Huber's formula for all species except E. regnans. When all species were combined, the centroid estimate was clearly more accurate, its mean error (-2%) being just significant (p=0.046). Centroid sampling also gave more accurate estimates of the volume of the component logs.

Results of this study and earlier work suggest that centroid sampling is applicable to tree species of both excurrent and deliquescent growth habit.     

The Growth of Radiata Pine On Lateritic Soils at Second Valley,South Australia

Factors involved in the growth of P. radiata (D. Don) on soils of a lateritic landscape have been examined by soil and foliar analysis and the measurement of ring width; this has given an appraisal of factors influencing growth in the past and at the present time.

Perched water tables, which often occurred in winter on the plateau where there were lateritic podzolic soils, did not depress growth. The addition of phosphate was essential, with responses lasting for about 8 years with superphosphate. Regression relationships between the annual growth increment (ΔV in cubic feet) and foliar levels of nitrogen (N) and phosphorus (P) were found for three different foliar sampling positions; these relationships had the form:

ΔV = 4.5%P + 0.28%N—0.47.

Considerable variation was found in the foliar levels of nitrogen, phosphorus, copper, zinc, boron, nickel, molybdenum, chromium and ash for different sample positions within the tree. Preliminary responses to nickel, copper and nitrogen were obtained on 15-year-old trees well supplied with phosphorus. Advisory foliar levels for nitrogen and phosphorus are given.     

Fertilising Eucalypts at Plantation Establishment on Farmland in south-west Western Australia

Responses of Eucalyptus species planted on farmland in the south-west of Western Australia to nitrogen (N) and phosphorus (P) fertilisation were investigated over two and three year periods. Factorial combinations of N (0, 6, 17 and 34 g per seedling) and P (0, 5, 12 and 24 g per seedling) in mostly water soluble (quick release) compounds were applied within a month of planting.

On well drained soils growth of E. globulus exceeded that of E sideroxylon and E. microcarpa by a considerable margin. After three years there were significant (p < 0.05) growth responses by E. sideroxylon to N and P and by E. globulus to P only. In contrast, the third species planted in that experiment (E. microcarpa) showed no significant growth response to N or P. The growth response of E. sideroxylon to a combination of the maximum levels of N and P represented improvements (compared to no fertiliser) of 69% in tree height and 265% in crown volume index. For E. globulus the improvements with each level of P > 0 g were consistently around 14% in tree height and 29% in crown volume index. Improvements in basal area and stem volume index increased with each level of P tested from 13% (5 g P) to 42% (24 g P) in the case of basal area and from 40% (5 g P) to 58% (24 g P) in the case of stem volume index. On poorly drained soils the only significant effect of fertilisaer treatment two years after the planting on the species tested (E camaldulensis, E cornuta and E. woollsiana) was that increasing N level increased seedling mortality. Average mortality rate for the three species increased from 20% (0 g N) to 30% (34 g N).

In other experiments, also with three species on both well drained and poorly drained soils, fertiliser rates were kept constant at 18 g P and 8 g P per seedling but the form and timing of fertiliser application was varied. However, it made no significant difference to survival or growth rates of any species whether the fertiliser was applied in granular or tablet form, at planting time or one month after planting.     

THE BUFFERING EFFECT OF TREES AGAINST FLUCTUATING AIR TEMPERATURE

Temperatures within trees were measured with thermocouples. Fluctuations of temperature three inches beneath the bark of Eucalyptus pilularis and E. rubida were one-third those on the surface. Temperature did not fluctuate during a 24-hour period at the centre of a tree 85 inches in girth. A sudden variation of 22 degC at the bark face was damped to a 1.5 degC change several hours later at the tree centre.     

Potential of two tree shelters to aid the early establishment and growth of three Australian tree species on the Darling Downs,south-east Queensland

The ability of the commercial tree shelter Growtube® and a perforated sheet metal shelter (Mauri) to improve the growth and survival of seedlings of Casuarina cristata, Eucalyptus moluccana and Melaleuca linariifolia was tested on the Darling Downs in south-east Queensland. The 0.9 m high tree shelters were removed after 2 years and at this time tree survival was unaffected by shelter type for all 3 species. Over a 44-month period, neither shelter improved the height growth of C. cristata or E. moluccana. Growtubes significantly (P < 0.05) increased the height of M. linariifolia and, at the time of shelter removal, trees in Growtubes were 23% taller than control trees. Differences in height decreased after the Growtubes were removed and 18 months later were no longer significant (P > 0.05). The early deterioration of the growtubes would have decreased their ability to create a beneficial microclimate, leading to the absence of any height increases for C. cristata and E. moluccana and small and non-persistent height increases for M. linariifolia. Thus, Growtubes were considered unsuitable for the environment in which they were tested. The cost of establishing a tree without a tree shelter, with a Mauri tree shelter and with a Growtube tree shelter was estimated to be $1.82, $3.08 and $5.12, respectively. During the first two years, a further $1.79 per tree was spent on materials used to replace damaged Growtubes.     

Neurophysiological basis of rehabilitation of adolescent idiopathic scoliosis

Background. Knowledge on mechanisms of neurophysiological control of trunk movement and posture could help in the development of rehabilitation programs and brace treatment in adolescent idiopathic scoliosis (AIS).

Aims. Reviewing up-to-date research on neurophysiology of movement and posture control with the aim of providing basis for new researches in the field of AIS rehabilitation and background understanding for clinicians engaged in management of AIS.

Methods. Review of literature.

Results. We considered several neurophysiological issues relevant for AIS rehabilitation, namely, the peculiar organization of patterns of trunk muscle recruitment, the structure of the neural hardware subserving axial and arm muscle control, and the relevance of cognitive systems allowing mapping of spatial coordinates and building of body schema.

Discussion and conclusion. We made clear the reason why trunk control is generally carried out by means of very fast, feedforward or feedback driven patterns of muscle activation which are deeply rooted in our neural control system and very difficult to modify by training. We hypothesized that augmented sensory feedback and strength exercises could be an important stage in a rehabilitation program aimed at hindering, or possibly reversing, scoliosis progression. In this context we considered bracing not only as a corrective biomechanical device but also as a tool for continuous sensory stimulation that could help awareness of body misalignment. Future research aimed at developing strategies of trunk postural control learning is essential in the rehabilitation of adolescent idiopathic scoliosis.     

GENERAL MEETING OF THE INSTITUTE HELD AT FORESTS DEPARTMENT,PERTH, ON SATURDAY, 7th DECEMBER, 1940, AT 10 a.m.

This paper discusses the effects of fire on the ability of specially reserved trees of Eucalyptus regnans, E. obliqua, and E, delegatensis (syngigantea) to produce a useful supply of seed for the regeneration of logged areas with a dense understorey of rain forest or wet sclerophyll scrub.

Observations are given on the fire resistance of these eucalypts at different ages and in different environments. The ecological consequences of various combinations of fire resistanos and types of fire are discussed.

The surface of the ground, in the moist cool forests of Tasmania, usually accumulates much raw humus. At the butts of mature eucalypts the humus forms a mound of amorphous, peaty, combustible material at least.several inches, and commonly several feet, deep. The humus can burn only after an unusually dry summer. A fire which consumes it will kill or severely injure all local tree species almost irrespective of bark thickness. Death is due to the killing of the cambium where the humus was burnt in contact with the bark. On the other hand, a fire which consumes only the surface fuels and leaves the humus intact will be much less injurious, especially to trees with thicker bark. Even a complete scorching of the crown is rarely lethal without trunk girdling.

Fire may accelerate the abscission of twigs, leaves, capsules and immature floral parts. The abscission of capsules is accompanied by accelerated seed shed. Immature floral parts do, however, often survive in good numbers provided the twig subtending them survives. Twigs may be killed either from girdling of the tree or by being directly scorched by radiant heat. The leaves and floral parts on killed twigs die, but are not abscissed. Seed shed occurs as soon as the capsules dry out. Seeds inside the capsules on the tree often survive in good numbers.

Because of these findings and because burnt ground becomes relatively unreceptive to eucalypt seed after 1–2 years, owing to excessive weed growth, it is unwise to rely on regeneration from any.seed crop which is not mature at the time of the fire.     

HIGHER FORESTRY EDUCATION IN AUSTRALIA

The results of three field trials which were established in 1976 to determine the feasibility of increasing wood production of Pinus radiata by fertilisation of thinned stands are described after four years of growth following the fertilisation treatments. The stands of about 20 years of age were producing an average of 14 m³ ha^?1 stem-wood per year.

The extra volume of wood growth resulting from fertilisation averaged 4.2 m³ ha^?1 a¹ for all sites, and 5.9 m³ ha^?1 a^?1 for the two most responsive sites, the latter being 37% over that obtained from unfertilised stands. Fifty per cent of the extra volume was added to the largest one-third of trees in the stands. A dominant tree of diameter (bhob) 27.0 cm in 1976 became 30.7 cm in 1980 if unfertilised and 32.8 cm if fertilised, an increase of 2.1 cm.

The responses obtained were inversely proportional to both the relative growth rates of unfertilised stands following thinning, and to the nitrogen concentration in the foliage of unfertilised trees measured in the year following fertilisation. Some soil/plant relationships have been examined for nitrogen, phosphorus, potassium and sulphur.

Fertilisation at this age appeared to at least ‘break-even’ if costs were amortised at an interest rate of 6%. However, fertilisation may also be a useful means of increasing yields at relatively short notice and allow increased flexibility in harvesting and other forest operations.     

LIST OF MEMBERS AND ASSOCIATES 1966

We irrigated 36 species and provenances of mainly Australian native trees with saline drainage water (EC 2 dS/m and boron 2.4 mg/L) in a trial sited at Loxton, in semi-arid south eastern Australia. Twelve months after planting, the survival rates amongst species were similar with a site mean of 96%. Three years after planting, the tallest trees were E. gomphocephala and the provenances/clones of E. occidentalis and E. camaldulensis, with heights ranging from 5.3 to 6.7 m; these trees also had the greatest girth with basal areas (measured at 0.3 m above ground level) ranging from 16 m²/ha to 24 m²/ha. The basal area and height of E. camaldulensis was highly variable ranging from 1 m²/ha and 2.1 m for the CML42 clone, to 16 m²/ha and 6.2 m for the Alcoa clone 20. Provenance also had a significant effect on the values of these parameters in E. occidentalis. In the third year, water use rates were determined for 12 of the better growing species. Over summer, the mean daily water use rates ranged from 49 L/tree for the Alcoa clone 20 of E. camaldulensis, to 12 L/tree for E. kondininensis. The Alcoa clone 20 of E. camaldulensis had the higher daily rate of water use per unit area of sapwood, 4.7 kL/m². The hourly rates of water use per unit area of sapwood rose with increasing vapour pressure deficit up to a value of about 17 hPa and then remained constant as VPD rose to 55 hPa. Variation amongst tree species in the relationships between hourly rates of water use per unit area of sapwood and VPD was highly significant.     

Weed control among planted and direct-seeded Eucalyptus,Acacia and Casuarina with the herbicides diphenamid,oryzalin, clopyralid and fluazifop-butyl

In a glasshouse pot trial, applications of the pre-emergence herbicide oryzalin at rates equivalent to 4 and 8 kg a.i. ha^?1 were toxic to germinating seeds of Eucalyptus maculata, Casuarina glauca and Acacia saligna. The pre-emergence herbicide diphenamid was toxic at rates of 7 and 14 kg a.i. ha^?1 to germinating C. glauca and A. saligna, but not to E. maculata.

Both oryzalin and diphenamid were selective at these rates when applied over newly-planted seedlings of Eucalyptus melliodora, Casuarina cunninghamiana and Acacia baileyana on a former pasture site. Diphenamid gave greater pre-emergence control of grass weeds, while oryzalin was more effective against the broad-leaved weeds. Overall, the most satisfactory long-term weed control and tree response was achieved with oryzalin.

The post-emergence herbicides fluazifop-butyl at 0.6 and 1.2 kg a.e. ha^?1 and clopyralid at 0.25 and 0.5 kg a.e. ha^?1, were mostly selective to the planted seedlings on the former pasture site, but they gave unsatisfactory weed control, probably because of a combination of poor timing of application and a herbicide-tolerant weed flora.     

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.     

Influence of trunk control and lower extremity impairments on gait capacity in children with cerebral palsy

Abstract

Purpose: We investigated the combined impact of trunk control and lower extremities impairments on predicting gait capacity in children with cerebral palsy (CP) and evaluated relationships between trunk control and lower extremities impairments.

Methods: Data of 52 children with CP [29 boys, mean age 11 years 9 months (±4 years 6 months)] were included in this observational study. Gait capacity was measured by the “modified Time Up and Go test”. Experienced therapists performed the “Modified Ashworth Scale”, “Manual Muscle Test”, the “Selective Control Assessment of the Lower Extremity”, and the “Trunk Control Measurement Scale”. We calculated Spearman correlations coefficients (ρ) and performed regression analyses.

Results: Trunk control was the strongest predictor (β?=?–0.624, p?<?0.001) when explaining the variance of gait capacity and remained in the model together with spasticity (R²?=?0.67). Muscle strength and selectivity correlated moderately to strongly with the trunk control and gait capacity (–0.68?≤?ρ?≤?–0.78), but correlations for the spasticity were low (ρ<–0.3).

Conclusions: The interconnection between trunk control, leg muscle strength and selectivity for gait capacity in children with CP was shown. It indicates the significance of these impairments in gait assessment and, potentially, rehabilitation.

• Implications for Rehabilitation

• Trunk control was the strongest predictor for gait capacity in a regression model with lower extremity spasticity, muscle strength and selectivity and age as independent variables.

• Lower extremity muscle strength, selectivity, and trunk control explained a similar amount of gait capacity variance which is higher than that explained by lower extremity spasticity.

• Lower extremity muscle strength and selectivity correlated strongly with trunk control.

• Therefore, we cautiously suggest that a combined trunk control and lower extremity training might be promising for improving gait capacity in children with CP (Gross Motor Function Classification System level I–III), which needed to be tested in future intervention-studies.