Nurse plants are species that help other plants grow by providing shelter and a safe microhabitat for seed germination and seedling growth beneath their canopy.
Pinyon pine shelters Joshua trees
Nurse plants are species that help other plants grow by providing shelter and a safe microhabitat for seed germination and seedling growth beneath their canopy.
In some higher-elevation parts of the Mojave Desert and nearby transition zones, pinyon pines (Pinus monophylla) can act as nurse plants for young Joshua trees (Yucca brevifolia).
Here’s how that works:
- Shade: The pinyon pine casts shade that protects Joshua tree seedlings from intense sunlight and reduces water loss.
- Temperature moderation: That same shade keeps the soil cooler during the day and warmer at night, helping the seedling avoid temperature extremes.
- Wind break: The pine also acts as a wind shield in areas where strong, drying winds can damage or desiccate seedlings.
- Moisture retention: The pine’s canopy helps trap moisture in the soil, creating a slightly more humid microenvironment.
This relationship is most likely to happen in ecotones—zones where desert and woodland environments overlap, such as parts of the Mojave’s upper slopes and sky islands. In these zones, both Joshua trees and pinyon pines can coexist, and the older pines sometimes help give the slow-growing Joshua trees a head start.
It’s a subtle but meaningful example of cooperation in nature, especially in a place as tough as the desert.