Vector Analysis: Does it really predict growth response?Mariann Johnston, SUNY-ESF Ranger School

Shoestring Satellite Experiment:The Adirondack Screening Trials

Individual tree fertilization trials James F. Dubuar Memorial Forest,

Adirondack Park 2 Species

Sugar maple (dom/codom, ~30 cm dbh)

Am. beech (intermediate, ~10 cm dbh)

6 Treatments screened

Shoestring Satellite Experiment:The Treatments

Control N1: 30 N (urea) N1P1: 30 N + 30 P (MAP + urea) N2: 200 N N2P2: 200 N + 100 P N2P2KB: 200 N + 100 P + 200 K + 3

B

One-time application

Shoestring Project Prelim

Timeline

2010 May: Fertilized, Measured July-Aug: Foliage collected, dried,

weighed 2011

Feb-Apr: ICP and C/N analyses July: Vector analyses presented Nov: Remeasurements

Today: Two-Year Basal Area Response

Vector Analysis

Foliar diagnostic technique Predicts nutrient deficiencies

Assumes that foliage response is a predictor of tree yield response

Did it work?

Sugar Maple

Vector analysis said:

Response to N2P2KB will occur N, P, K were deficient

Sugar Maple Growth Response

Contro

lN1

N1P1 N2

N2P2

N2P2K

B0.00.51.01.52.02.53.03.5

Treatment

2-Y

ear

BA

Resp

on

se

(%)

No significant differences between treatments

American Beech

Vector analysis said:

No growth response to any fertilization treatment will occur

Beech Growth Response

Control N1 N1P1 N2 N2P2N2P2KB0

5

10

15

20

25

30

Treatment

2-Y

ear

BA

Resp

on

se

(%)

0.003

0.090.17

0.020.07

p-values:

Conclusions

Did vector analysis predict growth response? No, not really (2-yr BA)

But . . . Foliage-damaging spring freeze

occurred at time of fertilization Height, volume growth were not

analyzed Continue monitoring for future

responses

Conclusions

Beech responded to fertilization! Intermediate crown class, understory

cohort Is beech a ‘nutrient hog’? What are the ecological implications?

The End

60 80 100 120 140 16060

80

100

120

140

160

Relative Nutrient Content

Re

lati

ve

Nu

trie

nt

Co

nce

ntr

ati

on

Graphical Vector Analysis100

A: Dilution

B: No Change

Relative Foliage Biomass

C: Deficiency

D: Luxury Consumption

E: Toxicity

F: Antagonism

Sugar Maple Growth

Mean dbh Yr 0: 34.6 cm Mean dbh Yr 2: 35.0 cm Average BA response of 2.4% No differences between

treatments were detected Predicted growth responses not

apparent in diameter response

Beech Growth

Mean dbh Yr 0: 9.9 cm Mean dbh Yr 2: 10.7 cm Average BA response of 18.1% All treatments showed significant (p

< 0.05) growth compared to control except for N2 (200 kg N)