Does Fertilization Make Trees More Thirsty?

Does Fertilization Make Trees More Thirsty?

Adan Hernandez Hernandez, UNHVirginia Hernandez-Santana, IRNAS, Seville, Spain

Heidi Asbjornsen, UNH

July 11, 2012.

Adan Hernandez Hernandez, UNHVirginia Hernandez-Santana, IRNAS, Seville, Spain

Heidi Asbjornsen, UNH

July 11, 2012.

INTRODUCION

• Many impacts of atmospheric deposition on forest dynamics have been studied: mortality, productivity, plant diversity, plant health, regeneration dynamics.

• Less is known about impacts on vegetation water use and water use efficiency implications for hydrologic cycle and water supply.

•A study in 2011 (Hernandez-Santana unpubl) showed no significant effects of nutrient amendments on plant water use after 5 months.

Research question

What are the effects of nutrient amendments on individual tree water use of the dominant species and on stand transpiration in young and mature forests in Bartlett Experimental Forest, New Hampshire?

Experimental design in Bartlett, NH

Young stand (24-year-old)

Mature stand (>100-year-old)

Sampling design

Stands DBH (cm) TreatmentsTotal

# treesTree species

Mature 21 - 34 N,P,NP,C 28

Yellow birch (YB)American beech (BE) Sugar maple (SM)

Young 12 - 15 N,P,NP,C 32

Pin cherry (PC)Red maple (RM)White birch (WB)

Data collectionData collectionSap flow stationHeat ratio method (Burgess et al., 2001)

Preliminary results: hourly sap velocity(one individual per treatment)

-5

0

5

10

15

20

25

30

35Mature Forest: American beech

NPNPCVs

(cm

h-1

)

4 6 5 7 8 9

June

3

-10

0

10

20

30

40

50

60

Young stand: Red maple

NPNPC

Vs (c

m h

-1)

3

4 5 6 7 8 9

June

Preliminary results: Hourly sap velocity(one individual per treatment)

Preliminary results: Mean hourly sap velocity (Vs): 10:00 am to 2:00 pm, 7-day average

N P NP C0

5

10

15

20

25

Mature (BE)Young (RM)Young (PC)

Treatments

Vs (

cm

h-1

)

• These preliminary results show a trend of greater sap velocity for Red maple in the Young stand compared to the American beech in the Mature stand.

• Sap flow calculation, more long-term data and statistical analyses are needed to assess significant differences in vegetation water use in response to nutrient amendment treatments.

Conclusion

I would like to thank Heidi Asbjornsen, Virginia Hernandez-Santana and my lab group.

Questions and suggestions