Category Archives: Trees

Shoot Pruning and Impact on Functional Equilibrium Between Shoots and Roots in Simultaneous Agroforestry Systems

Click to access InTech-Shoot_pruning_and_impact_on_functional_equilibrium_between_shoots_and_roots_in_simultaneous_agroforestry_systems.pdf

For that kind of intensive shoot pruning management (coppicing), it is important to select trees species that store adequate amounts of carbohydrates in the roots to provide the energy for resprouting and rapid regrowth of above ground parts. Shoot regrowth from other less intensive shoot pruning (pollarding or lopping) could be energetically supported from carbohydrate stores in stems and roots of the pruned tree stump.
The implications for associated crop management are several. Since shoot pruning removes competition for light between the tree and associated crop, it also provides a time window of almost one month when no competition in the soil can be expected between tree and crop roots for plant available nutrients. Transplanting of crop seedlings can then be made at shoot pruning to aid the early growth of seedlings. Depending on the needs of the crop, another shoot pruning of the agroforestry trees may be needed during the life of the crop, preferably before the onset of the reproductive phase of crop development.
Handarayan et al. (1997) suggested that the nitrogen mineralisation rate of prunings may be manipulated by mixing different quality materials such as high quality tree prunings of G. sepium and low-quality legume tree prunings such as Peltophorum dasyrachis (Miq.) Kurz. Pruning two weeks before transplanting vegetable seedlings and mulching with pruning may confer more efficient nutrient use on the agro-ecosystem.
The delay of hedge pruning until after the annual crop is established could result in greater water utilisation by the hedges and consequently, reduced evaporation.

Pollarding and Coppicing

Examples of trees that do well as pollards include broadleaves such as beeches (Fagus), oaks (Quercus), maples (Acer), black locust or false acacia (Robinia pseudoacacia), hornbeams (Carpinus), lindens or limes (Tilia), planes (Platanus), horse chestnuts (Aesculus), mulberries (Morus), redbud (Cercis canadensis), tree of heaven (Ailanthus altissima) and willows (Salix), and a few conifers, such as yews (Taxus)

In the days of charcoaliron production in England, most woods in ironmaking regions were managed as coppices, usually being cut on a cycle of about 16 years. In this way, fuel could be provided for that industry, in principle, indefinitely, as long as the nutrient mineral content of the soil was appropriately maintained. This was regulated by a statute of Henry VIII, which required woods to be enclosed after cutting (to prevent browsing by animals) and 12 standels (standards or mature uncut trees) to be left in each acre, to be grown into timber. The variation of coppicing known as coppice with standards (scattered individual stems allowed to grow on through several coppice cycles) has been commonly used throughout most of Europe as a means of giving greater flexibility in the resulting forest product from any one area. The woodland provides not only the small material from the coppice but also a range of larger timber for jobs like house building, bridge repair, cart-making and so on.

The splitting of large logs, whether for firewood or fencing, was a custom adopted by Americans in response to the conditions of their forests: vast numbers of huge trees covered the continent when the first settlers moved westward. In preindustrial Europe, the notion of growing a tree to a great size, only to chop it into small pieces, was seen as wasteful of human energy. Poles and timbers were grown to the size needed, and no more, while fire-wood was cut at just the dimension required for stoves and fireplaces.

Oak, ash, beech, and elm were commonly the standards, while hazel, alder, lime (linden, Tilia cordata), willow, and hornbeam were often grown in the understory. Hazel yielded not only edible nuts, but fodder from the young shoots, and like willow, made excellent basketry, while lime leaves were eaten and the trees usually allowed to flower before harvesting, to provide a flavored honey crop. Lime was also made into greenwood furniture, while hornbeam went for fuel, and alder (a nitrogen-fixer) bolstered soil fertility. Many of these same species have additional medicinal or craft use, providing dyes, seeds, and flowers of value.

Overstory and underwood were usually of different species. This made the woodland ecologically resilient, as canopy and ground cover exploited not only different soil layers and nutrients, but grew at different seasons. The coppice and groundcovers did about two-thirds of their photosynthesis for the year before the overstory came into leaf.


Interesting site on coppicing

Farmers actually only pollard trees during dry seasons, when the hay harvest falls short of their needs.  From mid-July through September’s end farmers harvest leaf fodder from hedge maple (Acer campestre), Norway maple (A. Platinoides), hornbeam (Carpins betulus), oriental hornbeam (C. orientalis), ash (Fraxinus excelsior), black mulberry (Morus nigra)oak (Quercus spp. – except for Q. cerris which is the animals do not eat), white willow (Salix alba), large leaved linden (Tilia platyphyllos) and elm (Ulmus spp.).  Only in years of severe feed shortage do they use European beech (Fagus sylvatica), while black alder (Alnus glutinosa) remains even less common.  They collect the nuts from hazel (Corylus avellana) and use the leaves medicinally to treat prostate problems and kidney disease in humans.

Thoughts on Baptisia australis (False Indigo)

B. australis grows best in lime-free, well-drained stony soil in full sun to part shade. It grows to about 90 to 120 cm tall (3 to 4 feet) in height with a similar spread. Like other members of the genus, it has a very deep taproot, which makes it quite difficult to move once planted. It thrives in full sun and requires water only in times of low rainfall. One slightly negative feature it that the leaves tend to drop early in the fall, but this may be avoided by cutting the dead stems as they die back. It is hardy in USDA zones 3 through 8.[4] It is commonly employed as a border plant in gardens.[5]

It almost seems like Legume plants drop their leaves early so that other things might thrive beneath them…


Click to access 63vansambeek-p-24.pdf

A study on nurse cropping nut trees with leguminous plants and trees. Results were not very telling.

The interplanting and underplanting of nodulated nitrogen-fixing plants in tree
plantings can increase early growth and foliage nitrogen content of hardwoods, especially black walnut and pecan. Recent studies have demonstrated that some non-nodulated woody legumes may be capable of fixing significant levels of atmospheric nitrogen. The following nine nurse crop treatments were established with and without interplanted northern pecan: the nodulated legumes black locust, false indigo, and smooth false indigo; non-nodulated thornless honeylocust, Kentucky coffeetree, and redbud; non-leguminous buttonbush; 16N-8P-8K tree food spikes; and a control without shrubs or fertilizer. Average foliage nitrogen
content of the nurse trees ranged from 3.3 percent for black locust, false wild indigo, and smooth wild indigo, and 2.1 percent for honeylocust and Kentucky coffeetree, to 1.8 percent for redbud and buttonbush. In the fourth growing season, pecan foliage nitrogen was similar across all treatments (1.8 to 2.0 percent); however, black locust had increased pecan foliage nitrogen to 2.2 percent in the sixth growing season. Pecan growth is similar across all treatments except when interplanted with black locust that overtopped the pecan and is suppressing its growth. Interpretations include the possibilities that soil nitrogen was adequate to preclude any benefits from biologically fixed nitrogen, that nurse plants did not release sufficient fixed nitrogen to increase pecan growth, and foliage nitrogen in non-suppressed saplings, or that other soil factors are limiting pecan development.