When herbaceous pasture becomes scarce, forage shrubs and trees can provide leaves, shoots, browse, flowers and fruit. These resources diversify livestock diets and may become particularly valuable during summer, winter and other critical periods.
Herbaceous pasture forms the basis of feeding in many extensive livestock systems. Its availability and quality, however, do not remain constant throughout the year.
Low rainfall and high temperatures reduce the supply of grass during summer. In winter, cold weather, frost or snow may also restrict plant growth. Prolonged droughts and other adverse conditions can further limit the food available to livestock.
Under these circumstances, woody vegetation becomes especially important. The LIFE ScrubsNet document “Livestock and scrub management for dehesa regeneration” explains that shrubs and trees can provide a wider variety of food resources throughout the year. Their leaves, shoots, browse, flowers and fruit can supplement livestock diets when herbaceous pasture is limited.
A feed reserve within the holding
Forage shrubs are species capable of regrowing after grazing and whose leaves and woody shoots have suitable palatability and nutritional value.
Their presence creates a food reserve distributed across the holding. They may be conserved or planted in hedges, field boundaries, patches, open woodland formations and other areas compatible with livestock production and conservation objectives.
The aim is not to replace herbaceous pasture entirely, but to create a more diverse and staggered supply of forage. Some plants provide leaves, while others produce shoots, flowers or fruit at different times of the year.
This diversity can reduce dependence on a single food source and improve the holding’s ability to respond to periods of shortage.
Leaves, browse, flowers and fruit
Shrub vegetation can provide different resources depending on the species and the season.
Livestock may browse leaves and tender shoots directly. Pruned branches from shrubs and trees can also provide useful fodder at particular times.
Some species produce flowers or fruit that animals can consume. Acorns are particularly important in the dehesa, while wild olives, carob pods and other woodland fruits may also contribute to livestock feeding.
The protocol also notes that some shrubs contain compounds with nutraceutical properties. Plant diversity therefore provides more than additional biomass: it allows animals to select among species with different nutritional characteristics.
Particularly valuable during summer
Summer is one of the most difficult periods for Mediterranean extensive livestock farming. Herbaceous vegetation dries out and progressively loses quality, while livestock require more water and shade.
At this time, evergreen shrubs and certain tree species may retain part of their green biomass. Hedges, riparian formations and woody vegetation in cooler areas can provide browse or green fodder after the herbaceous layer has dried.
The document identifies several drought-adapted species with forage potential, including wild olive, tree lucerne, tagasaste and different Atriplex species.
Not every species is suitable for every location. Selection must take account of local climate and soil conditions, potential invasiveness and applicable regulations.
A winter resource as well
Woody vegetation can also be important during winter.
The use of holm oak browse is a traditional practice in the dehesa, particularly when low temperatures restrict grass availability. Pruning remains and harvested branches can supplement livestock diets during this period.
Woodland fruit provides further seasonal resources. Acorns play a central role in feeding Iberian pigs during the montanera, while other fruits may be used by different livestock species and wildlife.
Vegetation with different production cycles can therefore extend the period during which the holding provides its own feed resources.
What makes a suitable forage shrub?
Not every shrub is equally appropriate for livestock feeding. According to the protocol, a useful forage species should:
- produce abundant leaves, shoots or fruit;
- have suitable nutritional value and no significant toxicity;
- be palatable to livestock;
- tolerate pruning and browsing;
- regrow effectively after use;
- be adapted to local environmental conditions;
- present a low risk of invasive behaviour.
It is also beneficial for the shrub to allow herbaceous pasture to grow beneath its canopy and to integrate into the vegetation mosaic without displacing other valuable species.
Diversifying both diet and landscape
Shrubs provide more than forage. Hedges, patches and small woodland formations can offer shade, shelter from wind and protection during periods of heat or cold.
They can also conserve soil, improve water retention, add organic matter and provide habitat for pollinators, birds and beneficial wildlife.
Maintaining a degree of woody vegetation diversity therefore combines productive and environmental functions. The same hedge may feed livestock during a critical period while also protecting soil and acting as a biodiversity corridor.
Using the resource without exhausting it
When grass is scarce, livestock increase their consumption of shrub vegetation. This can be beneficial, but it requires careful control.
Excessive pressure may cause animals to consume new shoots repeatedly, reduce the shrubs’ capacity to regrow and damage young holm oaks or cork oaks developing within the vegetation.
The risk is particularly high in areas reserved for regeneration. During spring, when tender new growth appears, excessive stocking can remove both the shrub layer and the young trees it is intended to protect.
Stocking rates, grazing dates, occupation periods and subsequent recovery time must therefore be adjusted carefully. Shrubs are a strategic reserve, but they can only continue to perform this role if they retain their ability to recover.
Planning before scarcity arrives
Woody forage resources should not be considered only after feed has already become scarce. Their conservation and management need to be planned in advance.
Identifying existing species, understanding when they produce leaves or fruit, protecting selected patches and organising their use can integrate these resources into the holding’s annual management calendar.
The LIFE ScrubsNet message is clear: a dehesa with greater plant diversity has more options for coping with critical periods.
Conserving forage shrubs and trees can diversify livestock diets, reduce vulnerability to seasonal shortages and combine livestock production with the conservation and regeneration of the system.
The LIFE ScrubsNet project is co-funded by the European Union through the LIFE programme, LIFE20 NAT/ES/000978.