Thirty-seven houses on a cherry orchard.

Eichler built at volume in Palo Alto and Sunnyvale and barely at all in Los Altos. Fallen Leaf Park is the only tract he completed in the city — thirty-seven houses laid out across 1968 and 1969 on a former cherry orchard, along three streets: Fallen Leaf Lane, Clay Drive and Alexander Way.

That number is the entire market. There is no second phase, no adjacent tract, no infill. When a house here trades, the buyers who wanted it have usually been waiting years, and roughly one in twelve of them has already been through our hands.

Lots run to about ten thousand square feet, which is generous for an Eichler tract anywhere and genuinely unusual in Los Altos at this price. The lot is a large part of why these houses hold value differently from the Palo Alto tracts, where lots are frequently half the size.

By 1968 the plans had grown, the rooflines had become more complicated, and the street elevation had closed down hard in exchange for a much more private interior. A Fallen Leaf Park house gives the street almost nothing — a garage door, a fence, a gate — and opens completely to the back and to the middle.

The tract is dominated by atrium plans, and that is the single most important fact about it. An atrium is the one thing that cannot be added to a house later at any price. Elsewhere it is the exception; here it is close to standard.

Floor plans run from three bedrooms at roughly two thousand square feet up to a rare five-bedroom model, including one laid out in the shape of an H. The largest of them is Claude Oakland's plan HPO-15, which is drawn out in full on the main page.

On a post-and-beam house the interior partitions carry almost nothing, which is why they move so readily. Sixty years in, almost every house in this tract has had its kitchen opened, a bedroom converted, a wall taken out. That is normal and it is not damage.

What does not move is the frame — the beams, the glass line, the roof planes and the atrium. Those are the parts that determine what the house is, what it is worth, and what it will cost to put right if a previous owner got them wrong. Original mahogany, intact glazing and an unaltered roofline are worth real money here, and a boxed-in atrium or a filled-in glass wall is a discount you should be pricing.