Pear trees which are not thinned annually to remove immature excess fruits can be triggered into a biennial bearing cycle, where they fruit normally (in a healthy tree) one year and minimally the next, since they need to recoup energy for fruiting. It would be understandable if a tree this large wasn't thinned regularly in terms of fruit or even branch pruning, so that may have been one factor.

'Magness' is not self-fruitful and requires pollination from another European pear variety in order to fruit. (European pears can be pollinated by ornamental flowering pears as well, such as 'Bradford' and other Callery Pear types. Since this group is invasive, though, we don't recommend using them as a pollinator.) Your other pear, 'Kieffer', might not be a suitable pollinator for 'Magness', though you could look for pollinator compatibility charts that include both varieties to be more certain. Since the pollen of 'Magness' also happens to be sterile, that means that it would need to be grown along with two other pear varieties, so one or both of those others could pollinate 'Magness' while their pollen can cross-pollinate each other. (Self-pollination is not a common trait for pear varieties. 'Kieffer' is one that actually can self-pollinate, at least somewhat.) Was an ornamental pear tree (or another fruiting pear) growing in the area a few years ago which has since been removed, therefore taking away a pollen contributor? If so, that might explain the poor fruiting of the 'Magness' in the past few years.

Overall tree health also plays a role in fruiting potential. Fire blight is a serious disease of pears, and while 'Magness' has good resistance (none are completely immune), the symptoms of infection would be quite prominent. The bare branches pictured are not showing these classic indicators of fire blight, so either the cause was another issue or the attached dead leaves that can be a hallmark of infection fell off a while before the photo was taken. Do you recall what the initial symptoms were when the branch dieback began?

It's hard to tell from the state of the canopy pictured what caused the dieback. Does the downspout outlet pipe in the photo empty near the pear's root zone (which reaches at least as wide as its branch spread), or does it carry stormwater further away? Pears are somewhat tolerant of heavy clay soils, but not very tolerant of wet soils, "wet feet," or poor drainage. In heavy rain events, extra water deposited into the root zone could hamper growth or even kill roots, which would then result in some branch dieback. Declining tree canopies can indicate a problem with root health if there is no clear indicator of an above-ground infection like fire blight or apple scab or rust fungi, which can also cause a degree of defoliation.

There could also be delayed dieback from branch damage done by egg-laying periodical cicadas a couple years ago. While not a serious tree pest, some tree specimens sustained heavier damage than others, and secondary factors might be overlapping to kill branches that were wounded but otherwise remained alive at the time the damage was done. Scars from cicada egg-laying would still be visible, though fading, on the thinner portions of branches, though their presence doesn't necessarily mean they are linked to any dieback.

Competition for nutrients and water (during drought) from the neighboring shrub(s) could be hampering growth and fruiting in the pear, at least to some extent. Of course, you won't be able to have much impact on what may be happening in the tree's root zone (more root competition, for instance) on the other side of the property line.

Since all dead branch ends need to be pruned off regardless of the cause of dieback, and the tree overall may still need corrective pruning in regards to removal of crowded branches (similar to the 'Kieffer' tree), it might be simpler to remove the 'Magness' tree and begin with a new specimen. We realize you want to save the tree, but that could take years of intervention to restore it to health and the ability to fruit normally and abundantly. If you do replace it, an updated list of recommended European pear cultivars for the mid-Atlantic include:

• 'Bell'
• 'Blake’s Pride'
• 'Cold Snap'
• 'Harrow Crisp'
• 'Harrow Delight'
• 'Harvest Queen'
• 'Honeysweet'
• 'Moonglow'
• 'Potomac'
• 'Seckel'
• 'Shenandoah'

Preventing squirrels from pilfering the harvest is not really feasible, unfortunately. Scare devices (fake owls, reflective Mylar strips that blow in the breeze, etc.) might work for a time but will ultimately not deter them for long. This is especially true where squirrels have multiple access points into the tree, such as scrambling up its trunk as well as jumping into the canopy directly from a nearby building, tree, or power line. While enveloping the entire tree in bird netting (which also helps to exclude squirrels) might work to protect the harvest, that type of netting is more often utilized on smaller fruit trees and shrubs, and might risk accidentally trapping wildlife, such as entangling snakes or catching on bird feet if they attempt to land on it.

Miri