Infrastructure

Paddocks and laneways

Case Study: Trees for shade

Background

The existing farm (108 ha) has been planted out with about 28,000 trees over the past 20 years. The owners have acquired another 35 ha and eventually this will also be planted out.

Costs were subsidised initially by a local agroforestry project.

The primary aim was to provide shade and shelter for the dairy herd. The agroforestry potential was seen as a secondary benefit to the property, as their focus was milking cows – not growing timber.

In the early 1990s the property reconfigured the farm layout and planned the renewal of internal fencing. The project provided a great opportunity to renew fencing at a subsidised rate.

The property developed a whole farm plan that matched soil types and trees species, aligned paddocks and proposed tree plantings to maximise shade and shelter for the summer and winter months.

As part of the whole farm plan, areas of the property were also re-lasered which allowed separate bays to be constructed specifically for tree plantings. This allowed the trees to be strategically watered – separate from the irrigation bays which the herd accessed for grazing.

The tree bays were ripped and trees planted in late December, and also in autumn using root stock and bare-rooted trees. The property found it easier to manage weeds with the late December plantings.

Bays were planted out with 4-6 rows of trees, which incorporated different species to provide upper and lower storey cover (i.e. both shade and shelter in a single paddock).

Furrows adjacent the plantings were used to direct irrigation water to the trees, which also minimised the spread of water in the bays and subsequent weed growth.

Species planted included – red gums, flooded gums, spotted gums, iron bark, grey box, yellow box, black box, melaleuca, acacia wattle, West Australian swampy yate.

Swampy yate was planted along fence lines that bounded channels. The leaves from this tree fall on the ground and release a weed-repelling toxin. This is beneficial as the farm is certified biodynamic and is unable to use synthetic fertilisers or chemicals for weed control and reducing grass growth in and around the banks of the channels.

Note the north-south orientation of plantings. Cattle can access shade

all day simply by shifting from eastern to western side of the paddock

in the afternoon.

The majority of fences are still in place, segregating

the tree planting bays and the irrigation (grazing) bays.

Trees for shade and shelter

The main laneways leading to and from the dairy have established plantings. Cows are therefore happy to travel to and from the dairy during hot weather.

The daily milking routine remains unchanged regardless of the weather conditions. The cows are provided with shade and shelter every day, therefore it has never been an issue walking the herd to the dairy.

Over the past 10 years the property has never seen a cow enter the dairy showing signs of heat stress (e.g. excessive panting).

The cows utilise the tree shade and shelter as required. The herd usually seeks shade when the temperature exceeds 25°C (in summer this is usually around 10 am).

The herd has access to tree bays to control grass and weeds, however they prefer to stand on the green grassed irrigation bays than directly under the trees. It appears the grassed bays provide a cooler environment than the tree bays where there is no green grass in the summer months. The dry areas under the trees reradiate heat from the ground – grassed areas don’t re-radiate as much heat.

If strong cool winds are present in the winter the herd can be put in the ‘bush block’ with some hay. The thick tree density provides shelter from the winds. The dry areas under the trees re-radiate heat from the ground – grassed areas don’t re-radiate as much heat.

If strong cool winds are present in the winter the herd can be put in the ‘bush block’ with some hay. The thick tree density provides shelter from the winds.

Combination of upper and lower storey plantings –

providing both shade and shelter.

Trees on the southern side of the laneway – cows prefer to walk

under the canopy which is shaded in the afternoon.

What would you change?

Knowing what you know now...

Mark says that they’d reduce the number of rows planted per bay – 4-6 is too many. With low water allocations trees can out-compete perennial pastures in adjacent irrigation bays, especially if there is a dry spring and no water available for irrigation. However, if water is available then both trees and pasture can co-exist without affecting each other.

Tree belts running east – west should have no more than 2-3 rows to avoid pugging paddocks in winter and excess shade.

If a single row of trees is planted ensure multiple varieties are used to produce an upper and lower storey, otherwise the shelter component will be insufficient. Mark believes he planted too many tall eucalypts and not enough smaller ‘habitat’ trees.

Trees indigenous to their area are more likely to survive than trees adapted to other environments.

If planting out paddocks exclusively for young stock and dry cattle there is less need for shade, as compared to lactating cows. Young heifers are content to sit in the sun, while a lactating cow will seek shade in comparable temperatures.

An original six-row planting – understorey

strategically grazed by the herd.

Well-cambered laneways draining away from the trees –

dairy in the background.