Trees in agriculture, and in particular a dairy farming landscape, are a hard sell. Especially when it starts to take up productive area of a paddock, let alone the mess they can make if a storm passes by and creates an entire clean up job. The question for the industry then becomes what other benefits are these trees providing for the farmers stock and pasture?
Research by AgResearch, funded by Our land and Water, has tested some of the preconceptions about trees on farms using a Miraka farm run by Graham Smith. The farm is unique because it has combined dairy with dense plantings of Chinese timber tree, Paulownia, over the last two decades.
As the report says:
The greatest perception around trees grown on farm, and in particular a productive pastoral system, is that pasture production will drastically decrease. Previous research has shown that there can be a range of a 15% increase to a 77% decrease in pasture production under trees (Hawke and Tombleson 1993; Devkota et al. 2009). This is dependent on a multitude of factors including tree species, planting density and time of year. This project has looked into two key aspects, 1) Demonstrating the impact of trees on pasture production; and 2) Determine how cows use a grazing space planted with Paulownia trees compared to a typical barren pasture environment.
Check this cute little video of the farm.
And the conclusion? The study was brief (six months) and restricted to just one property. But the conclusions were fairly clear. The pasture did indeed suffer in the shade and led to less feed for the cattle – but the cows benefit from the shade, a highly relevant feature in a hotter climate. The question now is what is the optimal combination of shade and open field?
Trees absolutely have their place in agriculture and the future of farming. Finding the optimal amount of stems per hectare that aligns with offering shade to the cows and the hypothesized increase in pasture production through dryer summers must be evaluated to further influence the uptake of trees on farms in the New Zealand pastoral landscapes.
You can read the report here.