Water seedlings

How is the evidence assessed?
  • Effectiveness
  • Certainty
  • Harms

Study locations

Key messages

  • One replicated, randomized, controlled study in Spain found that watering tree seedlings increased survival during a dry summer but only increased the survival of some species during a wet summer, depending on the habitat. Watering increased or had no effect on seedling emergence depending on habitat and water availability.


About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

  1. A replicated, randomized, controlled study in 2004–2004 in one site in southern Spain (Mendoza, Zamora & Castro 2009) found that watering sown seeds increased or had no effect on the emergence and survival of trees, depending on species. In 2003, watering increased seedling emergence during the first two years for three of six species:  holly oak Quercus ilex (watered: 43–57%; unwatered: 37–49%), common whitebeam Sorbus aria (watered: 7–34%; unwatered: 4-24%) and common yew Taxus baccata (watered: 23–39%; unwatered: 1–9%). In 2004, at the same site, watering increased seedling emergence during the first two years for two of five species: Scotch pine in open areas and woodland (watered: 37–42%; unwatered: 22–24%), but not shrubland, and whitebeam in woodland (watered: 32%; unwatered: 12–28%), but not open or shrubland. In 2003, watering increased seedling survival of all six species during the first two years across all three habitats (watered: approx. 0–100%; unwatered:  approx. 0–90%; data taken from graphs). In 2004, watering did not increase seedling survival, except for Scotch pine in open areas and scrubland (watered: 2–39%; unwatered: 0–5%) and whitebeam in open areas (watered: 0–40%; unwatered: 0–19%). Experiments contained 180 (in 2003) and 90 (in 2004) plots (20 × 20 cm) across three open areas, scrubland and woodlands. Each plot contained the following seeds: 5 holm oak; 5 Pyrenean oak Q. pyrenaica; 15 Italian maple Acer opalus; 15 common whitebeam; 15 Scotch pine; 10 common yew (only in 2003). Half of the plots were watered during the year of sowing (2 l of water to a 30 × 30 cm area, frequency unknown). The year 2004 was wetter than 2003 (mean volumic water content of unwatered plots in summer: 2003: 8%; 2004: 18%).

    Study and other actions tested
Please cite as:

Agra, H., Schowanek, S., Carmel, Y., Smith, R.K. & Ne’eman, G. (2020) Forest Conservation. Pages 323-366 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.


Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

Forest Conservation

This Action forms part of the Action Synopsis:

Forest Conservation
Forest Conservation

Forest Conservation - Published 2016

Forest synopsis

What Works 2021 cover

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

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