Growing Poplar and Willow Trees on Farms, National - FAO

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5 Cost-benefit analysis of tree fodder From John Stantiall, Wilson & Keeling Ltd, Feilding Analysing the financial benefits of using poplars <strong>and</strong> willows as fodder trees is a challenging exercise, due to the range of possible scenarios <strong>and</strong> different perceptions about which costs should be included. The range of scenarios includes poplar trees – planted specifically for fodder or for erosion control – which are pollarded (branches cut back to a stump above browsing level) for drought feed; shrub willows which are grazed by sheep or cattle; <strong>and</strong> shrub willows used for dairy effluent management. Items often discussed with respect to inclusion in the analysis are the initial establishment costs, loss of grazing during establishment <strong>and</strong> labour costs. The analysis to date suggests that trees managed for fodder only may be cost-effective in some situations if the labour cost is not taken into account. Any particular analysis is only valid for the set of circumstances being studied <strong>and</strong> the assumptions made. For the purposes of this project, the farm systems where the trial blocks were grown were initially modelled because recorded information was available. Based on this information <strong>and</strong> a set of assumptions, several similar scenarios were developed to investigate the impact of variables, such as the percentage of effective farm area planted in trees. Ultimately, the model could be developed to the stage where farmers could input their own information <strong>and</strong> test the economic benefits of planting trees for fodder or dairy effluent disposal on their own farm. The following results are tentative, <strong>and</strong> may be modified over time as new information becomes available or the method is refined. 5.1 Pollarded poplars For a poplar block space-planted at 400 trees/ha, if the trees are harvested every three years, it is assumed that the pasture production is similar to a 65
lock without trees because a reasonable proportion of light still filters through to the pasture. Based on 2004-05 prices, the cost of establishing a pollarded poplar block is about $3,140/ha, or $1,680 if labour costs are not included. The model is based on the availability of edible dry matter, <strong>and</strong> assumptions made (based on farmer experience) about the difference in lambing percentages for the ewe flock <strong>and</strong> stock sale weights. Farmer experience indicates that ewes fed tree fodder have an increased lambing percentage of 3-5% compared with the others in a drought situation. Hence for the whole flock, the impact on lambing percentage will depend on the proportion of ewes that have access to the tree fodder. This is illustrated by the following example: Assumptions: • A pollarded poplar system. • Farm size of 600 ha. • Flock size of 1750 ewes. • Tree fodder comprises 15% of the ewe’s diet. • 120% lambing without any tree fodder. • 126% lambing with tree fodder. Area in trees (ha) Percentage of farm No. of ewes fed tree fodder Average flock lambing percentage 1.25 0.2 179 120 5 0.8 716 122 10 1.7 1433 123 From this table, it can be seen that the impact of a small area of trees is diluted across the total flock. While the extra lambs provide extra income, this relativity only occurs in the drought years. The stock performance advantage for fodder trees only occurs in the drought years (one year in five is used in the model). In the other four years, the farm with the trees has the same stock performance, but must continue to carry the extra costs. 66
Page 1 and 2:
Growing Po
Page 4 and 5:
CONTENTS 1 Poplars
Page 6:
Introduction Millions of poplars <s
Page 9 and 10:
was reported growing in Marlborough
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soils and desert a
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Eridano (P. deltoides × maximowicz
Page 15 and 16: ‘Crowsnest’), but are darker gr
Page 17 and 18: Available willow clones Tree willow
Page 19 and 20: managed to avoid heavy side-branchi
Page 22 and 23: 2 Establishing Poplar</stro
Page 24 and 25: The other steps to take before tree
Page 26 and 27: preventative for further slipping.
Page 28 and 29: 2.3 Planting poles Essentials of po
Page 30 and 31: Propagating on-farm material On the
Page 32 and 33: locks with newly planted poles, eve
Page 34 and 35: For converting a wet area to a brow
Page 36 and 37: systems; either as vegetation to be
Page 38 and 39: 3 Managing Poplars
Page 40 and 41: Use the right equipment Experienced
Page 42 and 43: egrowth from the trunk each year. A
Page 44 and 45: They were also stationary. Risers a
Page 46 and 47: Managing browse blocks These are hi
Page 48 and 49: At the tenth year following plantin
Page 50 and 51: limb growth, leading to breakout <s
Page 52 and 53: Herbicide use There are numerous la
Page 54 and 55: Timing Treatment earlier in the gro
Page 56 and 57: treatment so proceed cautiously <st
Page 58: What about roots thicker than 10 mm
Page 61 and 62: Create a ‘pruning nest’ A tree
Page 63 and 64: 4.3 Pests Possums There can be nume
Page 65: adult is reluctant to lay eggs on t
Page 69 and 70: established, the annual growth of e
Page 72 and 73: 7 Further information Public librar
Page 74: Guidelines to help land</st
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Growing Poplar and Willow Trees on Farms, National - FAO

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