deadForestCA {datana}

Data contains climatic, forest structure and forest mortality variable

Description

The data file contains one row per unique 3.5km grid cell by year combination. The data frame covers all grid cells within the state of California where at least one Aerial Detection Survey (ADS) flight was taken between 2009 and 2015, so each grid cell position has between 1 and 7 years of data (reflected as 1 to 7 rows in the data file per grid cell position). The main response variables are mort.bin (presence of any mortality) and mort.tph (number of dead trees/ha within the given grid cell by year).

Usage

data(deadForestCA)

Format

The data frame contains four variables as follows:

live.bah

Live basal area from the GNN dataset

live.tph

Live trees per hectare from the GNN dataset

pos.x

rank-order x-position of the grid cell (position 1 is western-most)

pos.y

rank-order y-position of the grid cell (position 1 is northern-most)

alb.x

x-coordinate of the grid cell centroid in California Albers (EPSG 3310)

alb.y

y-coordinate of the grid cell centroid in California Albers (EPSG 3310)

mort.bin

1= dead trees observed in grid cell. 0= no dead trees observed

mort.tph

Dead trees per hectare from the aggregated ADS dataset

mort.tpa

Dead trees per acre from the aggregated ADS dataset

year

Year of the ADS flight. Most flights occurred from May-August.

Defnorm

Mean annual climatic water deficit for the grid cell, for Oct 1-Sept 31 water year, averaged from 1981-2015

Def0

Climatic water deficit for the grid cell during the Oct-Sept water year overlapping the summer ADS flight of the given year

Defz0

Z-score for climatic water deficit for the given grid cell/water year. Calculated as (Def0-Defnorm)/(standard deviation in deficit among all years 1981-2015 for the given grid cell)

Defz1

Z-score for climatic water deficit for the given grid cell in the preceeding water year.

Defz2

Z-score for climatic water deficit for the given grid cell two water years prior.

Tz0

Z-score for temperature for the given grid cell/year.

Pz0

Z-score for precipitation for the given grid cell/year.

Defquant

FDCI variable. Quantile of Defnorm of the given grid cell, relative to the Defnorm of all other grid cells with a basal area within 2.5 m2 ha-1 of the given cell is basal area.

Source

The data were derived from the following repository doi:10.5061/dryad.7vt36, having details and data about the paper of Young et al (2017). This data frame was built, and used, for the research conducted by Salas-Eljatib et al (2018).

References

-Young DJN, Stevens JT, Earles JM, Moore J, Ellis A, Jirka AL, Latimer AM. 2017. Long-term climate and competition explain forest mortality patterns under extreme drought. Ecology Letters 20(1):78-86. doi:10.1111/ele.12711

-Salas-Eljatib C, Fuentes-Ramirez A, Gregoire TG, Altamirano A, Yaitul V. 2018. A study on the effects of unbalanced data when fitting logistic regression models in ecology. Ecological Indicators, 85:502-508. doi:10.1016/j.ecolind.2017.10.030

Examples

data(deadForestCA)    
head(deadForestCA)