CATS Tree Nutrition and Fertilization

Question 1

Which macronutrient is most commonly deficient in urban trees and is primarily responsible for chlorophyll production?

Accepted Answer

Nitrogen

Answer

Phosphorus

Answer

Potassium

Answer

Calcium

Question 2

What is the recommended soil pH range for optimal nutrient availability in most landscape trees in the Southwest?

Accepted Answer

6.0–7.0

Answer

4.5–5.5

Answer

5.5–6.5

Answer

7.5–8.5

Question 3

An arborist observes interveinal chlorosis on young leaves of a tree in an Albuquerque landscape. This symptom most likely indicates a deficiency of which nutrient?

Accepted Answer

Iron

Answer

Nitrogen

Answer

Potassium

Answer

Phosphorus

Question 4

Which fertilizer application method places nutrients directly into the root zone and is most effective for trees in compacted urban soils?

Accepted Answer

Deep root liquid injection

Answer

Surface broadcasting

Answer

Foliar spray

Answer

Trunk implant

Question 5

What is the primary purpose of a slow-release fertilizer formulation compared to a soluble fertilizer?

Accepted Answer

Reduced risk of fertilizer burn and extended nutrient availability

Answer

Lower cost per application

Answer

Faster uptake by tree roots

Answer

Better performance on sandy soils

Question 6

According to ISA best practices, the recommended nitrogen application rate for established shade trees per year is generally:

Accepted Answer

0.5–1.0 lb N per 1,000 sq ft of root zone

Answer

2–4 lb N per 1,000 sq ft of root zone

Answer

6–8 lb N per 1,000 sq ft of root zone

Answer

10+ lb N per 1,000 sq ft of root zone

Question 7

Which of the following symptoms is most associated with potassium deficiency in trees?

Accepted Answer

Marginal leaf scorch and tip dieback

Answer

Purple coloration of young leaves

Answer

Pale green color throughout the canopy

Answer

Distorted or stunted new growth