TV075
Vegetative Phenology observations at the Andrews Experimental Forest, 2009 - Present

CREATOR(S): Mark D Schulze

PRINCIPAL INVESTIGATOR(S): Mark D Schulze

ORIGINATOR(S): Mark D Schulze

OTHER RESEARCHER(S): Jay M. Sexton, Sarah Ward

DATA SET CREDIT:

Data were provided by the HJ Andrews Experimental Forest research program, funded by the National Science Foundation's Long-Term Ecological Research Program (DEB 1440409, DEB 2025755), US Forest Service Pacific Northwest Research Station, and Oregon State University.

METADATA CREATION DATE:

9 Apr 2009

MOST RECENT METADATA REVIEW DATE:

14 Jun 2019

KEYWORDS:

Populations, communities, populations, climate change, phenology, forest ecology, plant ecology, microclimate, air temperature, biodiversity, environmental gradients

PURPOSE:

The vegetation phenology study is part of a larger effort to understand the influence of climate variability and change on trophic interactions in mountainous terrain. The initial objectives are to investigate patterns of microclimate variability across Lookout Watershed and plant response to spatial and temporal variability in snowpack dynamics and winter and spring air and soil temperatures. The plant phenology efforts from 2009-2014 were coordinated with insect phenology and bird phenology sampling to improve understanding of how species across trophic levels respond to environmental variability, the extent to which climate variability may contribute to trophic asynchrony, as well as the potential for mountain microclimate diversity to buffer the effects of climate change. Over time, the research program will contribute to our understanding of how climate variability and change is influencing the timing and duration of the active growing period.

METHODS:

Experimental Design - TV075:

Description: This was designed to be an observational study of plant phenology across microclimate gradients within the Lookout creek watershed. Focal plant species were selected to represent major tree, shrub and herbaceous species that are well-distributed across the Andrews Forest. Sites were selected to capture variation in elevation, aspect and topographic position (see field methods for more detail). Observations were recorded for multiple marked individuals of each focal species at each site. The plant phenology study was integrated with temperature (MS045), insect (SA025) and bird (SA024) phenology studies to investigate the influence of microclimate and climate variability on trophic interactions.

Field Methods - TV075:

Description: Sixteen core phenology sites were selected based on locations of long term temperature (air and soil) and vegetation data (TV010) at reference stands. Distribution of study sites across elevation, aspect and topographic position was augmented by adding a few additional sites, and to create old growth and plantation paired sites at high, medium and low elevation. At these Core sites, air temperature was measured year round (see study code MS045) and plant phenology measured during springtime beginning in 2009 (Insect and bird sampling at these sites is detailed in databases SA025 and SA024). At each Core site a center point was established and plants from all of the 18 study species occurring in the area were added as encountered while inventorying a 25m radius circle around the center point until 5 individuals of each species were mapped and tagged (in the 2009 pilot season, only 3 individuals per species were added, the sample sizes were increased to 5 early in the 2010 season), or the search area was exhausted. In a few instances, plants of a given species were added up to 35m away from the center point to attain the target sample size. Mapping of each plant was done using bearing and distance from the center post. For herbaceous plants, individuals were marked using one or two pin flags with a numbered aluminum tag attached to the pin flag. Trees and shrubs were tagged using aluminum nails or zip ties depending on stem diameter. Marked individuals remain in the study until death, at which point a new individual is added to the sample. Plant phenology was observed ca. weekly by trained individuals using a species-specific scoring system for vegetative and reproductive phenophases. Observations began each year in late winter with the start date varying depending on observed winter weather, snowpack and plant condition across the elevation gradient, with the goal of initiating observations at each Core site prior to detectable phenological activity of focal plant species. The emphasis was on capturing spring phenology, so observations generally did not continue after full leaf expansion and flowering, and for late flowering species in relatively late springs we were not always able to capture the full spring reproductive and leaf expansion process. During winter and spring surveys observations of snow depth and percentage cover were recorded as comments for each core site.

Instrumentation: See MS045 for description of the temperature sensors used for microclimate monitoring. Phenology observations were made with the naked eye or 10x binoculars, depending on plant height.

TAXONOMIC SYSTEM:

USDA Plants Database

GEOGRAPHIC EXTENT:

HJ Andrews Experimental Forest

ELEVATION_MINIMUM (meters):

459

ELEVATION_MAXIMUM (meters):

1334

MEASUREMENT FREQUENCY:

weekly in spring; sporadically in winter and fall

PROGRESS DESCRIPTION:

Active

UPDATE FREQUENCY DESCRIPTION:

annually

CURRENTNESS REFERENCE:

Ground condition