Hubbard Brook Experimental Forest, NH Herbert Bormann Gene Likens - - PDF document

▶

Mar 06, 2023 115 likes •184 views

Hubbard Brook Experimental Forest, NH Herbert Bormann Gene Likens Robert Pierce (and others) Why would ecologists clear-cut a forest? Watershed #2 was clearcut in the winter of 1965-66 Herbicide applied in June 1966 to keep regrowth down CUT

SLIDE 1

Herbert Bormann Gene Likens Robert Pierce (and others) Hubbard Brook Experimental Forest, NH Why would ecologists clear-cut a forest? Does clearcutting change hydrology? pH dropped slightly and water temperature increased a little CUT Watershed #2 was clearcut in the winter of 1965-66 Herbicide applied in June 1966 to keep regrowth down

SLIDE 2

Hubbard Brook Nutrient Cycling Concentration in Stream Water (mg/l)

NO3

2-

CUT

scale change

1966 1967 1968 47 - 56 fold change (4600 - 5500% increase) Release of soil cations increased Ca2+ CUT Mg2+ K+ Al3+ Na+ 417% 408% 1558% 177% Mostly organic (humic) sources Mostly mineral sources > 1000%

SLIDE 3

INCREASED Nutrient retention in the system was impaired What are the main organisms and processes in the intrasystem cycle?

SLIDE 4

Allochthonous inputs Autochthonous regeneration Nutrient export Biotic storage Abiotic storage Energy Old-field succession time

SLIDE 5

Hubbard Brook Plant pool Stream fluxes Soil changes during succession

SLIDE 6