For the Sugar Pine Foundation (SPF) – a local non-profit dedicated to restoring Tahoe’s sugar pines and overall forest health – this September was incredibly busy with seed collection because 2024 proved to be a mast year for sugar pines and most conifers in the Tahoe region. This is significant because reforestation starts with collecting seed.

A “mast year” is when an entire population of a certain tree or shrub produces a large amount of fruit, seeds, or nuts, which are collectively referred to as mast. (The term “mast” comes from the Old English word mæst, which refers to the nuts of forest trees that accumulate on the ground.)

Mast years occur at irregular intervals every few years – and the timing is different for different species. Sugar pines, which take two years to produce fully mature cones, may mast every 2-7 years.

The exact reasons why trees mast are still a mystery to scientists, but factors that may play a key role include temperature, rainfall, and predation. In the Sierra Nevada, water is the most limiting factor for most plants and trees. To produce a healthy cone crop, trees need the right combination of moisture and temperature in the spring. The big snow year of 2022-3 along with last year’s wet summer may be the main reason behind many species experiencing a mast year in 2024.

While no one can really say why this year was a mast year, the SPF made sure to capitalize on the bumper crop of seeds and their field team didn’t have time to scratch their heads about it. They had to hustle to collect as much seed as possible because the early cold snap in August seemed to trigger sugar pine cones to open (or “flare”) earlier than ever before. Sugar pine cones look like long, sticky, green torpedoes towards the end of summer. Inside the green cones is the ripening seed.

Mid-September is usually when the SPF climbs known Major Gene Resistant (MGR) trees that can survive white pine blister rust and collects the cones while still green yet full of ripe seed. Cone collectors must get the green cones before they flare and drop their seed. This year, they had a very short window in the first week of September to collect the bumper crop of seed.

It is very important to collect seed during mast years because, quite simply, it delivers the most “bang for the buck.” When the trees are full of cones, it takes much less effort to collect a lot more seed in one given climb.

Mast years offer a great opportunity to store a lot of seed for future restoration needs. There is a general shortage of seed for wildfire restoration and planting needs in California, but mast years like this one can help re-stock seed banks since seed can keep for decades in cold storage.

The SPF harvests seed by sending a climber into the very top of trees laden with cones. The climber clips or shakes the cones off of the branches and a ground crew collects the fallen cones full of seed in burlap sacks. This year, the SPF’s pro tree climber, Benjamin Cavalier, scaled 8 resistant sugar pines, an incense cedar, and a western white pine to harvest cones in September. Maria Mircheva (SPF’s Executive Director), Edric Alvarez and Stephen Loane acted as ground crew.

The SPF team took advantage of this mast year by collecting seed from many species. The seed will be used for reforestation plantings in the Caldor Fire and other fires, such as the recent Davis Fire on Mount Rose.

This year, the SPF harvested:

• 55,000 sugar pine seeds
• 40,000 western white pine seeds
• 30,000 incense cedar seeds
• 20,030 mountain hemlock seeds
• 6,000 Jeffrey pine seeds

Thanks in large part to community donations of seed, the SPF already had 30,000 Jeffrey pine seeds in cold storage, which is why they didn’t harvest more of this species. This is the first time the SPF collected mountain hemlock seed and they look forward to raising and interplanting this species in higher elevation zones, such as in the Caldor Fire burn scar at Sierra-at-Tahoe.

Once collected and bagged, the SPF sends their cones to the US Forest Service Placerville Nursery for seed extraction. The first step of this process is to dry the cones on racks. Next, the cones are shaken in a machine to get the seeds out. Another machine is used to clean the seed.

Most of the seed the SPF collects gets stored in the freezer, but some is sent to nurseries to be grown into seedlings for restoration plantings. Half is shared with the US Forest Service for their restoration projects.

The first step in growing seedlings is to stratify the seed – which involves imitating fall, winter and spring by soaking the seed and keeping it refrigerated for three months – so that the seeds will sprout, or germinate, when it’s planted in Styro plug planters. The SPF gets the seedlings back from the nursery once they are one year old for restoration plantings in fire scars and other areas in need of rehabilitation around Lake Tahoe in the spring and fall.

You can help the SPF plant sugar pines and other native species where needed around South Lake Tahoe this fall! Check out their Planting Schedule and mark your calendar! You can also use the Calendar on their website to easily add any event to your own digital calendar!

Pioneer Trail Planting
Saturday, October 12 10 am – noon
Dirt parking area @ 38.892298, -119.973075

Sierra-at-Tahoe Planting
Sunday, October 13 9 am – 1 pm
1111 Sierra-At-Tahoe Rd, Twin Bridges, CA 95735
Join us to plant 1000 sugar pines and Jeffrey pines at the base of Sierra-at-Tahoe ski resort, which burned in the Caldor fire. This is our biggest public planting of the season and we need all of the help we can get! Wear closed toe shoes, sun protection, work gloves and bring some water. Lunch will be provided! Our planting will be happening as part of the 16th annual Keep Sierra Clean Day! Free lunch and lift rides are provided for the whole family!

Powerline Trail Planting
Friday, October 18 10 am – noon
2410 Alice Lake Rd, South Lake Tahoe, CA 96150

High Meadow Trailhead Planting
Saturday, October 19 10 am – noon High Meadow Rd, South Lake Tahoe, CA 96150

TRUCKEE RIVER DAY
Sunday, October 20 11 am – 1:30 pm
Sagehen Summit, 200 CA-89, California 96124 Come help plant sugar pines to restore forest diversity at Truckee River Day! Please register for this event at the Truckee River Watershed Council’s website and choose our Tree Planting project. Join us for FREE family fun and educational games at the River Fair at Granite Flat Campground afterwards from 1-4pm.

Tamarack Fire Planting
Saturday, October 26 10 am – noon
Exact location TBD

Truckee Scouts Planting
Sunday, October 27 1 pm – 3 pm
Sagehen Summit, 200 CA-89, California 96124

Truckee Planting with Patagonia
Friday, November 1
10 am – 2pm Exact location TBD