Articles containing the keyword 'pruning'

An ecophysiological growth process model, called INCA, for simulating the growth and development of a young walnut tree (Juglans regia L.) during three or four years, is presented. This tool, currently under development, aims at integrating architectural and physiological knowledge of the processes involved, in order to give a more rational understanding of the pruning operation. The model describes a simple three-dimensional representation of tree crown, solar radiation interception, photosynthesis, respiration, growth and partitioning of assimilates to leaves, stems, branches and roots. It supports the hypothesis that the tree grows as a collection of semiautonomous, interacting organs that compete for resources, based on daily sink strengths and proximity to sources. The actual growth rate of organs is not predetermined by empirical data, but reflects the pattern of available resources. The major driving variables are solar radiation, temperature, topological, geometrical and physiological factors. Outputs are hourly and daily photosynthate production and respiration, daily dimensional growth, starch storage, biomass production and total number of different types of organ. The user can interact or override any or all of the input variables to examine the effects of such changes on photosynthate production and growth. Within INCA, the tree entities and the surrounding environment are structured in a frame-based representation whereas the processes are coded in a rule-based language. The simulation mechanism is primarily based on the rule chaining capabilities of an inference engine.

• Le Dizès, E-mail: sl@mm.unknown
• Balandier, E-mail: pb@mm.unknown
• Cruiziat, E-mail: pc@mm.unknown
• Jacquet, E-mail: pj@mm.unknown
• Lacointe, E-mail: al@mm.unknown
• Le Roux, E-mail: xl@mm.unknown
• Sinoquet, E-mail: hs@mm.unknown

The material of the study consisted of 21 Scots pine (Pinus sylvestris L.) trees that had been pruned in the 1930’s and 1940’s. The butt log of the pruned stems was peeled into veneer from which the length and shape of the resin taps were determined. The length of the resin tap was affected in the first place by the knot diameter and the height of the knot along the stem. The length of the resin tap was about 1.5-fold that of the knot diameter. With an increase in the height above the ground of a knot, its length decreases. The resin taps were particularly long on poor sites and in the butt end of the stems, however, the variation in tap length was large both within and between the individual tree stands. The shape of the resin taps is presented in this study by diameter classes. The resin taps studied in the work were longer than those measured in other works. This may be due to the fact that the knots were uncovered by peeling instead of sawing.

The PDF includes an abstract in Finnish.

• Pietilä, E-mail: jp@mm.unknown

Empirical measurements showed that the strength of a dead branch of Scots pine (Pinus sylvestris L.) was related to the second power of the branch diameter and the third power of the basic density of branch wood. The same factors affected also the strength of living branches. Especially, the contribution of wood density was important. The significance of the results is discussed considering the natural process of self-pruning and its effect on the branchiness of the stem.

The PDF includes a summary in English.

• Kellomäki, E-mail: sk@mm.unknown

The material was obtained from Scots pine (Pinus sylvestris L.) stems which were pruned 27 years earlier up to the height of 5–6 m. Rotary cutting was made from 16 pruned stems and 3 unpruned ones. The length of bolts was 70 cm and the thickness of veneer 1.5 mm. The proportion of good quality veneer was 46% in pruned stems and 14% in the others. Veneer with exellent quality was obtained from pruned stems up to the height of tree meters, that is to say a little under the pruning line.
The PDF includes a summary in English.

• Laakso, E-mail: pl@mm.unknown
• Saikku, E-mail: os@mm.unknown

The material used in this study was collected in 1975 from a 41-years old curly birch (Betula pendula f. carelica Sok.) stand in Southern Finland, which had been pruned 12 years earlier. While the stand was thinned, 26 felled trees were selected for further study to study occurrence of discoloration originating from of pruned branches.

The study material included 35 pruned branch stumps and 38 naturally pruned branch stumps of curly birch. The mean diameter of the former was 31 mm and of the latter, only 15 mm. Of the pruned branch stumps, 23% had become completely sealed-off within 12 years. The discoloration had spread into the stem as little from pruned branch stumps as from naturally pruned ones even though the former were greater in diameter. Advanced rot was not found in any of the samples studied.

The PDF includes a summary in English.

• Raulo, E-mail: jr@mm.unknown
• Saarnio, E-mail: rs@mm.unknown
• Ylitalo, E-mail: ty@mm.unknown

On the basis of time studies on pruning, one thousand stems in four stands was pruned, carried out in 1962. The work was done in two phases with Olli pruning saw, first attached to a shaft about 1.8 metres long and the to a shaft about 4 metres long.

The total time of moving from one stem to another when pruning the stem varied from 0,28 to 0.31 min per stem in the different working sites. The resting time was 19–20% of the effective working time, which included actual pruning time and the moving time. In average, 7.5% of the actual pruning time was unproductive. The actual pruning took in average 0.75–1.1 min/stem in the different sites. The time depended on size of the tree, the DBH, and on the length of the part to be pruned. The total working site time for the pruning was in average 1.34–1.98 min/stem. The output of the work per 7 hours’ working day varied from 226 to 280 stems, and the costs from 10 to 14 pennies per stem.

The PDF includes a summary in English.

• Heiskanen, E-mail: vh@mm.unknown

Silva Fennica issue 42 includes presentations held in professional development courses, arranged for foresters working in public administration in 1936. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service

This presentation describes how pruning is used to produce quality timber.

• Lappi-Seppälä, E-mail: ml@mm.unknown

The objective of the present investigation was to clarify the profitability of pruning silver birch (Betula verrucosa, now Betula pendula Roth) in the growing of raw material for veneer industry. Calculations were made on the grade, value, and price of pruned and untreated butt logs as well as on costs of pruning and the development of pruned trees.

The grade distribution of unpruned veneer butt logs, the grade distribution of the veneer yield, and consequently, the value of veneer yield and log prices at the plant are considerably better than those of average logs. The grade, value and price increased with increasing diameter. The value and price of pruned butt logs depended primarily on the difference between the turning pruning diameters, and their increase with decreasing pruning diameter and increasing turning diameter. The value of pruned butt logs is always considerably higher than that of unpruned logs. The increase in the value correlates to the pruning and turning diameters, and is, for example, in rotary-cut logs which have been pruned when 10 cm in diameter 80–130%.

Pruning increases the stumpage in naturally regenerated silver birch stands on Oxalis-Myrtillus site by 2,000–3,000 Fmk/ha when employed at 20 years of stand age and rotary cutting at 60–80 years of age respectively. The average pruning costs on Oxalis-Myrtillus site are 51–57 Fmk/ha.

The PDF includes a summary English.

• Heiskanen, E-mail: vh@mm.unknown

The Scots pine (Pinus sylvestris L.) pruning experiments were established in different geographical regions of Finland. The pines were pruned in 16 different times during the year. Half of the trees were inoculated with conidia of Phacidium coniferarum (Hahn). Annual cankers were produced in the inoculated trees pruned during October–December. The safe pruning season ended in autumn when the five-day mean temperature decreased below +7°C. The unsafe pruning season terminated when the temperature remained permanently over 0°C. Dry-pruned branches were infected only if the phloem had been wounded. The mycelia of the fungus were pathogenic in the phloem in the inoculations made from October to March. The fungus occurred commonly in slash and in pines wounded during the autumn. The fungus has a one-year life cycle.

The PDF includes a summary in Finnish.

• Uotila, E-mail: au@mm.unknown

This paper investigates and models the effects of pruning season and tool on wound occlusion with varying tree and branch characteristics of silver birch (Betula pendula Roth) stems at the pruning height of 0−4 metres. Dates of eight secateurs prunings, three saw prunings and two sticks prunings as well as unpruned control were tested in permanent plots on four sites. Knot occlusion and discolouration in stemwood were measured from about 1600 studied knots of 112 sample trees felled five to six years after pruning in 2010. Knot occlusion rate was modelled according to pruning tool, date, tree growth, and branch characteristics. The occlusion was the fastest in trees pruned in spring or early summer, and the slowest in trees pruned in autumn. Stubs of living branches occluded faster than the dead ones with the same diameter. Saw pruning resulted in clearly better occlusion rates than secateurs pruning, caused by the shorter knot stubs after saw pruning. Hitting dead branches away with a stick resulted in the worst occlusion status. The colour defects spread more often upward from the knot than downward. Discolouration in stemwood was detected more frequently near to the pruned branches than the unpruned ones, and more widely near to the stubs of dead branches than the living ones. Most saw and secateurs pruned branches were completely occluded during the experiment, so these prunings were suitable for all branches under 20 mm in diameter, and for living branches even up to 30 mm in fast-growing trees.

• Niemistö, Natural Resources Institute Finland (Luke), Natural resources, Kampusranta 9 C, FI-60320 Seinäjoki, Finland E-mail: pentti.niemisto@luke.fi
• Kilpeläinen, Natural Resources Institute Finland (Luke), Production systems, Yliopistokatu 6 B, FI-80100 Joensuu, Finland E-mail: harri.kilpelainen@luke.fi
• Heräjärvi, Natural Resources Institute Finland (Luke), Production systems, Yliopistokatu 6 B, FI-80100 Joensuu, Finland E-mail: henrik.herajarvi@luke.fi

• Vartiamäki, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: henna.vartiamaki@metla.fi
• Hantula, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: jh@nn.fi
• Uotila, University of Helsinki, Hyytiälä Forestry Field Station, Hyytiäläntie 124, FI-35500 Korkeakoski, Finland E-mail: au@nn.fi

• Schatz, Peltotievantie 27, FI-99440 Leppäjärvi, Finland E-mail: us@nn.fin
• Heräjärvi, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: henrik.herajarvi@metla.fi
• Kannisto, Finnish Forest Research Institute, Parkano Research Unit, Kaironiementie 54, FI-39700 Parkano, Finland E-mail: kk@nn.fi
• Rantatalo, Peltotievantie 27, FI-99440 Leppäjärvi, Finland E-mail: mr@nn.fi