Boron and Herbicide
I have always believed in the phrase, (pictures are worth a thousand words).
For that reason, we look at three photographs, and give reasons why tree growth in these photographs is so exceptional.
Prior to moving to Canterbury in January 1978, I had it rubbed into me, by my work colleges from the NZ Forest Service, down in Otago, that you cant grow good trees in Canterbury.
After several decades in the province, I can see why this phrase was so common in earlier years because, in a lot of areas in Canterbury where weed growth, and boron deficiency is present, tree growth can be abysmal.
On the other hand, if weed suppression, and boron rich trees, are established in any part of Canterbury, particularly the foot hills, tree growth can easily compete with the best growth, anywhere in the country.
In the past, I have stressed the importance of moisture management. This is our most limited "nutrient" in Canterbury, and we should treat it like gold.
Drought, and boron deficiency are synonymous, and when this whole triangle has been sorted out tree growth is maximised. By controlling weeds you increase the moisture of your soil.
Tree size is directly related to the bare earth around the tree. Tree growth, and form, is greatly improved with a boron application. To apply a fertiliser without adequate weed control, can be detrimental to tree growth simply because, the weeds can more easily access the fertiliser than the trees, and hence can have a smothering effect on your newly planted plantation.
Matt Browns plantation in Bald Hills is very fertile, and both trees, and weeds, respond to this fertility.
Matt has been aware of this, and this photo shows his plantation where brush weed has been controlled through an aerial application, allowing the trees to maximise the site.
By completely aerial spraying the brush weed problem out, and applying boron at the start of the second growing season, Matt has maximised the growing potential of his plantation on this foothill forestry block. Notice the apical dominance which is a direct result from an early Boron application.
These trees are nearly 2 yrs old.
John Hawkins standing beside his plantation, up the Waipara Gorge .
Here weed competition was predominantly grasses, therefore 2 metre strip spraying was all that was required to maximise tree growth in this area .
These trees are nearly 2 years old, and have just recently received a boron application.
By controlling the weeds, and therefore increasing the soil moisture, boron levels can be doubled in the first 2-3 years of a trees growth, and in many cases since the Boron levels are increased due to increased moisture, a boron application can be delayed until after the second growing season.
Sammi McCord standing beside an aged P.radiata cutting which has been strip sprayed, and treated with boron at establishment .
This frosty site had two previous crop failures, but by targeting the correct plant, (aged cutting) and applying Boron at establishment, with good weed control, tree growth and survival is maximised .
This tree is not yet 1 year old .