This California law is called the Solar Shade Control Act. Its main aim is to encourage energy conservation and the use of alternative energy sources. It supports planting trees and shrubs for shade, temperature control, and other benefits. However, it also recognizes that trees and shrubs may need to be managed in certain situations to ensure they don't interfere with solar energy devices like solar collectors.

This law defines what constitutes a 'solar collector' for purposes of transforming solar energy into thermal, chemical, or electrical energy. A solar collector is usually a fixed structure on a building's roof used for heating water, controlling climate inside spaces, or generating power. If the roof is unsuitable, it can be installed on the ground. However, it cannot be used primarily to exceed the building's electricity demand. Solar collectors must follow local regulations and be placed at least five feet from property lines, and generally, ten feet above the ground unless specific setback adjustments are met.

If someone installs a solar collector, nearby property owners can't let trees or shrubs grow in a way that blocks more than 10% of the sunlight to the collector's surface between 10 a.m. and 2 p.m.

This law section outlines the notification process for building owners who plan to install solar collectors. If a solar collector is going to be installed, the building owner may send a "Solar Shade Control Notice" by certified mail to nearby property owners who might be affected by potential shaded areas. This notice must be sent within 60 days before installation and must include detailed information about the building owner's contact details, the solar collector's installation location, and the planned date of installation. If the installation date changes, a follow-up notice must be sent. It also allows for records of these notifications to be passed on to new building or property owners.

If you have a tree or shrub that blocks someone's solar panel, and they send you a written notice to fix it, you need to either remove or change the plant. If you don't, your tree or shrub becomes a "private nuisance," which is a legal term for something that bothers another person, like blocking sunlight from their solar panels.

This law specifies situations where certain rules do not apply to trees or shrubs in relation to solar collectors. If a tree was planted before a solar collector was installed, it's exempt from the rules. Trees grown for timber or commercial agriculture are also exempt. If a tree existing before a solar collector is replaced after dying or being removed to protect public health or safety, it is also not included. Moreover, any trees or shrubs governed by local city or county rules are not covered by this chapter.

This law allows cities or counties in California to opt out of the rules in this particular chapter through a local ordinance passed by majority vote. Such an ordinance won't need to comply with the California Environmental Quality Act. Additionally, if a city or county creates rules about tree preservation or controlling solar shade, those local rules will take precedence over state rules in that jurisdiction.

If you're planning a solar heating or cooling system that might affect a neighbor's active solar setup, you can ask a court for permission to proceed with your plans despite potential conflicts. The court could allow it if your system saves more energy overall than the active system it would affect.