To investigate the effect of plastic waste on mangrove trees with pneumatophores, 
we conducted a manipulative experiment on 42 young A. marina trees 
to quantify root growth, litter fall and tree survival in response to various degrees 
of plastic suffocation over a period of six weeks. 

The 42 trees that were selected for the experiment were disconnected 
from other individuals and were relatively similar in size 
(mean height: 1.8 m (+/- 0.4 m)). To overcome potential bias in tree mortality 
caused by confounding variables such as salinity, waves or size rather 
than by the treatments, the 42 trees were assigned to the four plastic treatments 
based on their height in such a way that all treatments had the same variation 
of tree size and tree position relative to the sea. 

The trees were then subjected to one of the four treatments: 
100% of the pneumatophores covered by plastic (13 trees) 
50% of the root zone covered by plastic (11 trees) 
an untreated control (10 trees) 
and a cable tie control (8 trees) 

In the two plastic cover treatments, trees received a plastic bag on individual
 pneumatophores, tied to the bottom of each root with a cable tie.

The effect of different amounts of plastic cover was assessed in terms of 
(1) pneumatophore growth (new pneumatophore development and pneumatophore extension), 
(2) tree stress (litter fall and leaf area index) 
(3) tree survival

ID = tree ID
Treatment = one of the four previously mentioned treatments
tree_height_baseline = the tree height measured at baseline in cm
dry_weight_leaves_wk_n = dry weight of the leaves that were collected in a net suspended underneath each tree canopy in the n^th week after treatment application
number of days before leaf collection_wk_n = the number of days that the nets were suspended underneath the tree canopy before emptying in week n
daily_litterfall_wk_n = dry weight/number of days before collection in week n
weekly_average_of_max_daily_windspeed (m/s)_wk_n = average of the maximum windspeed per day (data from the meteo station of semarang airport) during week n
vegetated_canopy_wk_6 = surface area (m^2) of original tree canopy still vegetated (Normalized Green Red Difference Index (NGRDI)> 0) at the end of the experiment. 
missing_canopy_wk_6 = surface area (m^2) of original tree canopy without green leaves (Normalized Green Red Difference Index (NGRDI)<0) at the end of the experiment.
lai_wk_6 = leaf area index at the end of the experiment (proportion of the original canopy surface, that is still covered by green leaves by the end of the experiment.
tree_survival_wk_6 = tree status: dead (0) or alive (1) at the end of the experiment.
 