Colorado Master Gardener Training Trees and the Living Soil
Trees: Soils & Fertilizers
80% of all tree disorders begin with soil problems. Predisposing Inciting Contributing
80% of all tree disorders begin with soil problems, most commonly soil compaction .
Preventing Soil Compaction
Avoid working clayey soils when wet
Annual applications of organic matter
Establish walkways, keeping traffic off growing beds and out of tree’s PRZ
Avoid excessive tilling
Aerate turf areas
Construction = Soil compaction
Aeration of Compacted Soils Correction is limited, prevention is the key.
Aerate lawn at 2” centers
Organic mulch in PRZ of trees
Soil fracturing with compressed air
Prevent Compaction within the PRZ Calculating the Critical Root Radius, CRR of the Protected Root Zone, PRZ 1. First measure the tree’s circumference (distance around) at a 4.5 foot height, in inches. 2. Divide the number by 2. 3. Express the results in feet. CRR Example: Circumference = 30 inches 30 2 = 15 CRR = 15 feet dripline Protected Root Zone (PRZ)