Posttransplant Root and Shoot Growth Periodicity of Sugar Maple

Fundamental information regarding posttransplant root and shoot growth dynamics is needed to better understand transplant establishment. Seasonal patterns of root, shoot, and trunk growth of balled-and-burlapped and pot-in-pot (PIP) sugar maples (Acer saccharum Marsh.) transplanted at leaf drop (Nov. 2000), late fall (Dec. 2000), early spring (Mar. 2001), budbreak (Apr. 2001), or budset (July 2001) were measured and compared with nontransplanted field- and PIP-grown trees. All trees exhibited a pattern of maximum shoot extension, root growth, and trunk expansion in early May, late May, and early June, respectively. Maximum root growth was concurrent with early trunk expansion, both of which began when shoot growth was decreasing. Root growth was characterized by periods of abundant growth in late May and early June and less growth in summer and early fall. Transplanting at fall leaf drop, in late fall or spring, or at budbreak did not appear to radically disrupt the normal growth periodicity of sugar maple. However, transplanting at budset (summer) resulted in abundant root growth 11 weeks later than the period of maximum root growth in all other treatments. Our data indicate that similar amounts of root regeneration can be expected for irrigated July-transplanted trees as for trees transplanted in fall and spring. As well, our study provides evidence of root mortality during the winter and spring after the first posttransplant growing season. Although minimal root mortality was evident in nontransplanted field trees, substantial root mortality was evident in the nontransplanted PIP trees during winter and early spring.

Root and Shoot Growth Periodicity of Kalmia latifolia `Sarah' and Ilex crenata `Compacta'

The length of time between transplanting and subsequent new root initiation, root growth rates, and root growth periodicity influences the ability of woody ornamentals to survive transplanting and become established in the landscape. Research was conducted to compare root growth of a difficult-to-transplant species, Kalmia latifolia L. (mountain laurel), to that of an easy-to-transplant species, Ilex crenata Thunb. (Japanese holly), over the course of 1 year. Micropropagated liners of `Sarah' mountain laurel and rooted stem cuttings of `Compacta' holly were potted in 3-L containers. Plants were grown in a greenhouse from May to September, at which time they were moved outside to a gravel pad, where they remained until the following May. Destructive plant harvests were conducted every 2 to 4 weeks for 1 year. At each harvest, leaf area, shoot dry weight (stems and leaves), root length, root area, and root dry weight were determined. Throughout the experiment, shoot dry weight and leaf area were similar for the two species. New root growth of `Compacta' holly and `Sarah' mountain laurel was measurable 15 and 30 days after potting, respectively. Root length and root area of `Sarah' mountain laurel increased during May through December but decreased during January through May. Root length and root area of `Compacta' holly increased linearly throughout the course of the experiment. Final root: shoot ratio of `Sarah' mountain laurel was one-ninth that of `Compacta' holly. Results suggest that poor transplant performance of mountain laurel in the landscape may be related to its slow rate of root growth.

Growth Periodicity for Container-Grown Red and Freeman Maple Cultivars in AHS Heat-Zone 8

Growth patterns of seven red maple (Acer rubrum L.) and three Freeman maple (Acer x freemanii E. Murray) cultivars grown in containers in Alabama were evaluated using monthly destructive harvests. The effectiveness of a growth modeling technique not previously described is demonstrated using the data presented for both the Freeman maple (red maple xsilver maple interspecific cross) and red maple categories. Freeman maple cultivars ‘Armstrong’, ‘Celzam’ (Celebration™), and ‘Jeffersred’ (Autumn Blaze™); and red maple cultivars ‘Autumn Flame’, ‘Fairview Flame’, ‘Landsburg’ (Firedance™), ‘Franksred’ (Red Sunset™), ‘Olson’ (Northfire™), ‘Northwood’, and ‘October Glory®’ were studied. Uniform liners of each cultivar were planted in 9.1-liter (#3) containers in March 1996. More than 75% of seasonal height and diameter growth was complete for most cultivars before mid-August, while only 25% of root growth had occurred by the end of August. The remaining 75% of root growth occurred from August through November. The greatest overall growth (based on height, diameter, and root growth increase) was for ‘Autumn Flame’ and ‘October Glory®’, both red maple cultivars; and Freeman maple cultivars ‘Celzam’ and ‘Jeffersred’. The least overall growth (based on height, diameter, and root growth increase), was for red maple cultivars ‘Northwood’ and ‘Landsburg’.

Influence of Rainfall, Irrigation and Age on the Growth Periodicity and Wood Structure in Teak (Tectona Grandis)

Growth periodicity was followed for two consecutive annual cycles to reveal the pattern of wood fonnation in plantation-grown teak at three different localities in India. Rainfall and age were the two important factors that influenced cambial activity. Cambial reactivation occurred during March-April in both years. The pre-monsoon showers broke the cambial donnancy at all three localities. Almost a month's interval was observed between bud break and initiation of radial growth . Irrespective of age and locality, a peak period of cambial activity occurred during June-July. Dormancy began during October-December, depending on the age of the trees and locality. Juvenile trees and those grown in relatively high rainfall areas had a prolonged cambial activity and retained foliage throughout the year. They produced wider rings with higher proportions of latewood. Irrigation of 5-year-old trees led to the loss of typical ring porosity of teak wood; their first three growth rings were more or less diffuse-porous. This is attributed to uninterrupted cambial activity resulting in production of rather uniform-sized vessels.

Growth periodicity of introduced pastures on the northern tablelands of New South Wales

This paper reports on the growth periodicity of introduced temperate perennial pastures in a summer-rainfall environment in the high-rainfall zone of eastern Australia. Data were derived from an experiment (1985-87) directed at evaluating pasture cultivars when sown in binary mixtures grazed by sheep. The data were also simulated by using the decision support system SheepO (Version 4·0) and validated by visual techniques, deviance measures, and statistical tests. The model simulated pasture growth rate and total biomass with acceptable accuracy. The study provided a quantification of the growth rhythm of temperate perennial pastures in this environment. The data show that growth rhythm comprises a high growth rate (>50 kg DM/ha·day) during the primary growth cycle in spring, a moderate growth rate (20-50 kg DM/ha·day) during the secondary growth cycle in summer-autumn, and low growth rate (<20 kg DM/ha·day) in winter. The growth performance of introduced pastures based on cv. Demeter tall fescue (Festuca arundinacea) exceeded that of pastures based on cv. Sirosa phalaris (Pharlaris aquatica) in all seasons, at low and high stocking rates, and in all 3 years. The results highlight the potential for pasture cultivars with enhanced seasonal growth rate to increase the pasture feed supply for grazing animals.

Root and Shoot Growth Periodicity of Green Ash, Scarlet Oak, Turkish Hazelnut, and Tree Lilac

The objectives of this study were to determine root and shoot growth periodicity for established Fraxinus pennsylvanica Marsh. (green ash), Quercus coccinea Muenchh. (scarlet oak), Corylus colurna L. (Turkish hazelnut), and Syringa reticulata (Blume) Hara `Ivory Silk' (tree lilac) trees and to evaluate three methods of root growth periodicity measurement. Two methods were evaluated using a rhizotron. One method measured the extension rate (RE) ofindividual roots, and the second method measured change in root length (RL) against an observation grid. A third method, using periodic counts of new roots present on minirhizotrons (MR), was also evaluated. RE showed the least variability among individual trees. Shoot growth began before or simultaneously with the beginning of root growth for all species with all root growth measurement methods. All species had concurrent shoot and root growth, and no distinct alternating growth patterns were evident when root growth was measured by RE. Alternating root and shoot growth was evident, however, when root growth was measured by RL and MR. RE measured extension rate of larger diameter lateral roots, RL measured increase in root length of all diameter lateral roots and MR measured new root count of all sizes of lateral and vertical roots. Root growth periodicity patterns differed with the measurement method and the types of roots measured.